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Dermatopathology

Updated! Dermatopathology Signs & Diseases

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Sign or disease on the left is associated with signs or diseases on the right.
abscess, intraepidermal
blastomycosis, bromoderma, incontinentia pigmenti, iododerma, pemphigus vegetans
acantholysis
acantholytic dyskeratotic epidermal nevus, BCC, GVH (acute), persistent acantholytic dermatosis, solitary dyskeratosis, transient acantholytic dermatosis
acantholysis, primary
Darier’s d., Grover’s d., Hailey-Hailey d., herpesvirus infection, pemphigus foliaceus, pemphigus vulgaris, staphylococcal scalded skin s., warty dyskeratoma
acantholysis, secondary
actinic keratosis, impetigo, SCC (adenoid dyskeratotic), subcorneal pustular dermatosis, viral vesicles
acantholytic dyskeratosis
acantholytic dyskeratotic epidermal nevus, Darier’s d., transient acantholytic dyskeratosis, warty dyskeratoma
acantholytic dyskeratosis, focalacral lentiginous MM, BCC, CNCH, DF, melanocytic nevus, PR
adnexae, decreased
morphea, necrobiosis lipoidica diabeticorum, PSS, radiodermatitis
adrenoleukodystrophy
vacuolated eccrine secretory coils
amyloid deposits
amyloidosis, BCC, Bowen’s disease, nevi, pilomatrixoma, porokeratosis, SCC, SK
amyloid ring
ring around lipocytes; primary amyloidosis
annulate lamellae
EM finding; intracytoplasmic membrane composed of parallel cisternae with dilation of their edges; apocrine gland cells (normal), apocrine hidrocystoma, eccrine porocarcinoma, liposarcoma, malignant mesenchymal tumor, melanoma, rhabdomyosarcoma
Antoni A patternuniform spindle cells arranged in apposition outlined by reticular fibers; Schwanomma 
Antoni B patternelongated Schwann cells arranged end to end; Schwanomma 
apoptotic bodies
see colloid bodies
apoptotic keratinocytes
"dead reds;" dead keratinocytes in the epidermis:  EM, fixed drug eruption, GVH, lichen nitidus, lichenoid tissue reaction, LP, lues (secondary), LE, Merkel cell carcinoma, paraneoplastic pemphigus, phototoxicity, poikiloderma
asteroid bodies
stellate eosinophilic inclusions of collagen in macrophages or multinucleated giant cells; actinic granuloma, actinomycosis, coccidioidomycosis, elastolytic annular granuloma, leprosy, lobomycosis (asteroid body-like), NLD, sarcoid, sporotrichosis, tuberculosis
arabesque  
azurophilic granules, giant
giant primary granules within neutrophils; Chediak-Higashi d.
Azzopardi phenomenon
DNA-encrusted intratumoral blood vessels; oat cell metastases (from lung)
B cells, cancers
CLL, follicular lymphoma, mantle zone lymphoma, small lymphocytic lymphoma
B cells, decreased
lymphopenic agammaglobulinemia, SCIDS, thymoma with immunodeficiency, X-linked agammaglobulinemia
ball & claw
elongated rete ridges on sides of infiltrate; lichen amyloid, lichen nitidus, trichoepithelioma
ballooning degeneration of epidermis
intracellular edema; epidermolytic hyperkeratosis, herpes simplex, smallpox, variola, varicella, verruca
bannana bodies
EM finding; bannana shaped lipid vacuoles in Schwann cells; lipogranulomatosis (Farber’s d.)
basophils
contact dermatitis, incontinentia pigmenti
bean bag cells
histiocytes after phagocytosis of lymphocytes, erythrocytes, platelets; cytophagic histiocytic panniculitis
Birbeck granules
EM finding; tennis racquet-shaped bodies in Langerhan’s cells & congenital self healing reticulohistiocytosis, histiocytosis X, reticulum cell sarcoma, monocytic & hairy cell leukemia (some)
birds eye cells
koilocytes; flat warts
birefringence
amyloidosis, collagen, gout, hair, silica, uric acid crystals
bramble bush elastic fibers
penicillamine-induced elastic fibers
broad based budding
blastomycosis
bullae, hemorrhagic
bullous amyloidosis, EBA, erysipelas, gas gangrene, lichen sclerosis, PCT
calcification
cutaneous cartilage tumor, cutaneous endometriosis/endosalpingosis, epidermal inclusion cyst, penile fibromatosis (Peyronie’s d.), peripheral giant cell granuloma, peripheral ossifying fibroma, infantile fibromatosis (congenital fibromatosis), infarcted lipomas, lupus profundus, microcystic carcinoma, minor salivary gland calculus, pancreatic fat necrosis, pilomatrixoma, pseudotumor of Ehlers-Danlos s., PXE, sclerema neonatorum, synovial sarcoma, trichilemmal cyst, trichoepithelioma (desmoplastic)
capillaritis
familial pigmented purpuric eruption, gravitational purpura, purpura annularis telangiectoides (Majocchi’s d.), lichen aureus, pigmented purpuric lichenoid dermatosis of Gougerot & Blum, itching purpura of Doucas & Kapetanakis, Schamberg’s d.
cartilage
aponeurotic fibromatosis, branchial cleft cyst, cutaneous cartilage tumor, epithelioid sarcoma, extra-skeletal chondrosarcoma, fibrosarcoma, giant congenital nevus, mixed tumor (chondroid syringoma), proliferative myositis, schwannoma (malignant)
caseation necrosis
dermal collagen degeneration; lupus miliaris disseminatous facei, tertiary syphilis, tuberculosis
caterpillar bodies
PAS-positive globules on roof of blister containing basement membrane, degenerating keratinocytes, colloid bodies; PCT
cauliflower fibrils
see collagen flowers
CEA+
epithelioid sarcoma, granular cell tumor, intraepidermal epithelioma, Paget’s d., signet ring cell carcinoma, syringocystadenoma papilliferum
cells, two types
clear cell hidradenoma, cylindroma, eccrine spiradenoma
cementasome body
see Odland body
ceroid-like macrophage inclusions
Hermansky-Pudlak s.
chicken wire pattern
characteristic pattern of myxoid DFSP
cholesterol crystals
xanthoma cells, necrobiotic xanthogranuloma, pilar cysts
cholesterol granulomas
thymic cysts
cholesterolosis
erythema elevatum diutinum, North American blastomycosis
church spire appearance
marked papillomatosis with suprapapillary thinning of epidermis; acrokeratosis verruciformis of Hopf, erythrokeratoderma viriabilis, hyperkeratotic SK
cigar shaped nucleismooth muscle cell nuclei shape
civatte bodies
apoptotic keratinocytes in lichen planus
clear cells
balloon cell nevus, BCC, clear cell acrospiroma, clear cell hidradenoma, clear cell sarcoma, congenital nevi (early age), eccrine carcinoma, deep & penetrating nevus, malignant acrospiroma, renal cell carcinoma, trichilemmoma, SCC, sebaceous carcinoma, syringoma, white sponge nevus
cleavage, intra-epidermal
eczematous dermatitis, epidermolysis bullosa simplex, epidermolytic hyperkeratosis, EM, friction blister, herpes simplex, herpes zoster, incontinentia pigmenti, miliaria rubra, variola
cleavage, lamina densa
dystrophic epidermolysis bullosa, EM, lichen sclerosis, PCT
cleavage, lamina lucida
BP, cicatricial pemphigoid, dermatitis herpetiformis, heat, herpes gestationis, junctional epidermolysis bullosa, liquid nitrogen, PCT, pseudoporphyria, suction blister
cleavage, subcorneal
bullous diabeticorum, bullous impetigo, epidermolysis bullosa simplex, erythema toxicum neonatorum, friction blister, miliaria crystallina, pemphigus erythematosus, pemphigus foliaceus, SSSS, subcorneal pustular dermatosis
cleavage, subepidermal
BP, cicatricial pemphigoid, DH, EM, herpes gestationis, lichen planus, lichen sclerosis et atrophicus, linear IgA dermatosis, lupus erythematosus, PCT, urticaria pigmentosa
cleavage, supra-basal
Darier’s d., Hailey-Hailey d., pemphigus vegetans, pemphigus vulgaris, transient acantholytic dermatosis
coat sleeve infiltrate, coat sleeving
dense lymphocytic infiltrate around blood vessels of papillary & upper reticular dermis; EAC - Erythema annulare centrifugum
collagen flowers
abnormal collagen fibril aggregates creating a flower-like appearance on cross section; Buschke-Olendorf s., cutis laxa, Ehlers-Danlos s., OI, PXE AKA composite fibrils, cauliflower fibrils
collagen phagocytosis
multicentric reticulohistiocytosis
collarette
metastatic melanoma, pyogenic granuloma
colloid bodies
eosinophilic degenerated keratinocyte clusters; benign lichenoid keratosis, colloid milium, GVH d., KA, lichen nitidus, lichen planus, lichen striatus, lupus erythematosus, normal skin, poikiloderma AKA apoptotic bodies, Civatte bodies, cytoid bodies, hyaline bodies
comma bodies
EM; cytoplasmic curved lipid vacuoles in histiocytes, fibroblasts, & Langerhan’s cells; benign cephalic histiocytosis, generalized eruptive histiocytoma, histiocytosis X, infantile self healing reticulohistiocytosis, juvenile xanthogranuloma, multicentric reticulohistiocytosis, sinus histiocytosis with massive lymphadenopathy
composite fibrils
see collagen flowers
copper pennies 
intermediate vegetative form of chromoblastomycosis (pathognomonic) AKA medlar bodies, muriform cells
corneocyte
retention; ichthyosis vulgaris, x-linked ichthyosis
proliferation; epidermolytic hyperkeratosis, lamellar ichthyosis
coronoid lamella
wedge shaped parakeratotic column; actinic keratosis, BCC, eccrine ostial & dermal duct nevus, milium, porokeratosis, punctate keratoderma, seborrheic keratosis, scar, SCC, wart
corps grains
oval, basophilic dyskeratotic cells in stratum corneum; Darier’s d., warty dyskeratoma
corps ronds
dyskeratotic acantholytic basophilic keratinocytes with pyknotic nucleus & perinuclear halo; AK, Bowen’s d., Darier’s d., focal acantholytic dyskeratosis, Grover’s d., Hailey-Hailey d., keratoacanthoma, lichen striatus, proliferating trichilemmal cyst, SCC, warty dyskeratoma
Cowdry Type A intranuclear inclusions
Herpesvirus infections
crow's foot patterncharacteristic pattern in myxoid DFSP 
curvilinear bodies
see comma bodies
cutaneous horn
conical hyperkeratotic papule; AK, BCC, SCC, SK, trichilemmoma, trichilemmal keratosis, verrucae
cytoid bodies
see colloid bodies
cytoplasmic inclusions, pleomorphic
multicentric reticulohistiocytosis
decapitation secretionapocrine adenoma, apocrine hidrocytsoma, hidradenoma papilliferum, syringocystandenoma papilliferum, tubular apocrine adenoma 
dell
depression of epidermal surface; desmoplastic trichoepithelioma, LE, lichen sclerosis
dermal fibrosis
acquired digital fibrokeratoma, acroangiodermatitis, angiofibroma, atrophoderma of Pasini & Perini, BCC, Bleomycin administration, blue nevus, collagenoma, cutaneous endometriosis, ductal adenocarcinoma, eccrine spiradenoma, familial & nonfamilial cutaneous fibroma of tuberous sclerosis, fibrous papule of the nose, glomus tumor, hypertrophic scar, intraepithelial epithelioma, keloid, lobomycosis, LSA, lues, Merkel cell carcinoma, metastases, morphea, nevus sebaceous, pearly penile papules, pinta, prurigo nodularis, PSS, radiodermatitis, radiotherapy, spider bites, Talwin injection, morpheaform BCC, desmoplastic trichoepithelioma, SCC, shagreen patch, spindle & epithelial cell nevus, Spitz nevus, syringoma
dermal thickening
scleredema
dermolytic pemphigoid
epidermolysis bullosa acquisita (immunopathologic type)
desmoplasia
dense collagenous hypocellular stroma; desmoplastic spindle cell tumor, desmoplastic trichoepithelioma, epithelioid cell tumor
desmosome absence
BCC, indeterminate cells, Langerhan’s cells, sclerodermoid GVHD
desmosome proliferation
benign mucosal pemphigoid
desmosomes, intracytoplasmic phagocytized desmosomes in cytoplasia of keratinocytes: Bowen d., Darier d., extrammammary Paget, KA, MM, normal keratinocytes, SCC 
dilapidated brick wall
appearance from acantholysis throughout epidermis; Hailey-Hailey d.
doubly refractile
cholesterol esters (but not free cholesterol, phospholipids, or neutral fat), DF, EED, Fabry d., gout (urate crystals), Hand-Schuller-Christian d., JXG, lipids in tuberous and plane xanthomas, silica, splinters, suture, talcum powder, xanthelasma of hyperlipoproteinemia
Downy cellatypical lymphocytes in EBV infection 
dumbbell shape
cellular blue nevus
dyskeratosis, focal acantholytic
acantholytic acanthoma,BCC, CNCH, comedone, condylomata acuminata, Darier’s d., dermatofibroma, fibrous papule of the nose, Grover’s d.,keratosis punctata palmaris et plantaris, linear epidermal nevi,melanoma, nevi, oral leukoplakia, papillomas, papular acantholytic dyskeratosis, PR, PRP, psoriasiform dermatitis, SCC, seborrheic keratosis, warty dyskeratoma
dyskeratotic cells
eosinophilic, shrunken keratinocytes with pynknotic nuclei from abnormal keratinization; acrodermatitis enteropathica, acute GVH, candidiasis, dermatitis herpetiformis, DLE, EM, fixed drug eruption, IP, insect bites, intraepidermal epithelioma, keratoacanthoma, lichen planus, lichen sclerosis, lichen striatus, lichenoid photodermatitis, LE, lymphomatoid papulosis, lymphogranuloma venereum, measles, necrolytic migratory erythema, neutrophilic eccrine hidradenitis, parapsoriasis, pemphigus erythematosus, phototoxic contact dermatitis, PLEVA, proliferating trichilemmal cyst, pseudolymphoma, radiotherapy, SCC, secondary syphilis, solar chelitis, toxic shock s., verrucous incontinentia pigmenti, viral infection, warty dyskeratoma
elastic fiber (gain)
actinic elastosis, dermatofibrosis lenticularis disseminata, Ehlers-Danlos s., elastofibroma, juvenile elastoma, lichen sclerosis, mixed tumor (chondroid syringoma)
elastic fiber (loss)
acrodermatitis chronica atrophicans, actinic elastosis, acrokeratoelastosis, adenoma sebaceum, angiofibroma, annular elastolytic granuloma, anetoderma, acquired digital fibroma, atrophoderma, collagenoma, cutis laxa, digital fibrokeratoma, elastosis perforans serpiginosa, hypertrophic scar, keloid, leprechaunism, med dermal elastolysis with wrinkling, NLD, necrobiotic xanthogranuloma, nevus sebaceous, progressive nodular histiocytoma, radiodermatitis, restrictive dermopathy, striae, Talwin dermatitis, xanthoma disseminatum (phagocytosis of elastic fibers)
elastic fibers (intraepidermal)
elastosis perforans serpiginosa, keratoacanthoma, SCC
elastin accumulation
Buschke-Ollendorff s., elastoderma, elastofibroma, pseudoxanthoma elasticum, solar elastosis
emperipolesis macrophage filled with non-digested lymphocytes; sinus histiocytosis with massive LAD 
eosinophilic spongiosis see spongiosis, eosinophilic 
eosinophils, intraepithelial
halogenodermas, incontinentia pigmenti, keratoacanthoma
epidermal atrophy
acrodermatitis chronica atrophicans, actinic keratosis, atrophoderma, dermatomyositis, GVH d., lentigo maligna, lichen planus, lichen sclerosis et atrophicus, lupus erythematosus, poikiloderma, radiodermatitis, scleroderma, steroid atrophy
epidermal giant cells
pityriasis rosea
epidermal necrosis
erythema multiforme, glucagonoma s., GVH d., hydroa vacciniforme, ischemia, TEN
epidermolytic hyperkeratosis
thickened granular layer with perinuclear halos & swollen keratohyalin granules; actinic cheilitis, actinic keratosis, BCC, benign solid hidradenoma, bullous congenital ichthyosiform erythroderma,dermatofibroma, linear epidermal nevi, epidermolytic keratosis palmaris et plantaris,GA, hypertrophic scar, intradermal nevus, interferon alpha-2b administration, lichenoid amyloidosis, nevus comedonicus, nummular eczema, sebaceous hyperplasia, solitary acanthoma, trichilemmal cyst   AKA granular cell degeneration
epidermotropism
lymphoid cell influx to epidermis; large plaque parapsoriasis, metastatic malignant melanoma, mycosis fungoides
epithelial membrane Ag+
Merkel cell carcinoma
epithelial microabscesses
CTCL, histiocytosis X, migratory stomatitis (geographic tongue)
erythrocytes in epidermis
allergic contact dermatitis, drug eruptions, eczematous dermatitis, graft rejection, insect bite, leukocytoclastic vasculitis, lymphomatoid papulosis, PLEVA, pityriasis rosea, polymorphous light eruption
erythrocytes, extravasated
acroangiodermatitis, angiolymphoid hyperplasia with eosinophils, apocrine cystadenoma, cat scratch d., cellulitis, cutaneous cartilage tumor, cutaneous endometriosis, dermatofibroma, erythema annulare centrifugum, erythema multiforme, erythema nodosum, erythropoietic protoporphyria, granuloma faciale, Henoch-Schönlein purpura, Histiocytosis X, Kaposi’s sarcoma, lymphomatoid papulosis, meningococcemia, metastatic tumors, migratory panniculitis, parapsoriais variegata, pellagra, peripheral giant cell granuloma, pityriasis rosea, polymorphous light eruption, psoriasis lupus erythematosus, PLEVA, PMLE, RMSF, ruptured follicular cyst, Schamberg’s d., secondary lues, subacute nodular chancroid, Sweet’s s., toxic shock s., tuberculosis verrucosa cutis, tularemia, vasculitis
erythrophagocytosis
amebiasis, brucellosis, cytophagic histiocytic panniculitis, familial lymphohistiocytic reticulosis, histiocytosis X, malignant histiocytosis, regional histiocytosis, pancreatic fat necrosis, peripheral giant cell granuloma, pyoderma gangrenosum, regressing atypical histiocytosis
erythropoesis, dermal usually in infants: ABO/Rh incompatability, hereditary spherocytosis, infection (CMV, coxsackie virus, rubella), stress, twin transfusion s.
exocytosis
actinic reticuloid, eczema, MF, parapsoriasis en plaque, PLEVA, pityriasis rosea, secondary lues
extracellular cholesterosis
(cholesterol clefts); apocrine cystadenoma (hidrocystoma), EED, necrobiotic xanthogranuloma
extramedullary hematopoiesis
giant cell nevus, neurocristic hamartoma
Farber bodies
see comma bodies
festooning
round, irregular papillary dermal projections into subepidermal blister; BP, EBA, EPP, PCT
fibrinoid deposits
vessel wall fibrin deposition; dermatomyositis, leukocytoclastic vasculitis, rheumatoid nodules, subcutaneous granuloma annulare, SLE
fibrous long-spacing collagen
EM finding; angiofibroma (tuberous sclerosis), BCC (stroma), blue nevus, juvenile hyaline fibromatosis, lepromatous leprosy, melanoma (stroma), SCC (stroma), Schwannoma, scleroderma
fingerprint bodies
eccrine gland cells; ceroid-lipofuscinosis
flame figures
eosinophils, histiocytes & debris surrounding collagen fibers; arthropod bites, dermatophytosis, eczematous dermatitis, eosinophilic cellulitis, hypereosinophilic s., parasites, pemphigoid, prurigo nodularis
florets
conidia that form daisy-like clusters at hyphal branch ends; S schenkii
foam cells
lipid laden macrophage; juvenile xanthogranuloma, leishmaniasis, lepromatous leprosy, reticulohistiocytic granuloma, Weber-Christian d.(idiopathic lobular panniculitis), xanthoma
follicular plugging
Darier’s d., lichen sclerosis, LE, pemphigus erythematosus, PRP, seborrheic dermatitis
formalin fixation stable
CEA, EMZ, kappa and lambda chains, keratin epitopes, leukocyte common antigen, myelin basic protein, S-100, salivary mucin, von Willebrand’s related antigen
germinal centers
angiolymphoid hyperplasia with eosinophilia, angiomatoid malignant fibrous histiocytoma, lupus panniculitis, malignant fibrous histiocytoma, necrobiotic xanthogranuloma, pseudolymphoma, reactive lymphoid hyperplasia, tick bite granuloma
ghost cells
pale eosinophilic cell with central clearing & absent nucleus; fat necrosis, pilomatricoma AKA shadow cell
giant cells
actinic keratosis, angiofibroma, annular elastolytic granuloma, atypical fibroxanthoma, blastomycosis, Candida granuloma, cat scratch d., chromomycosis, coccidioidomycosis, cryptococcosis, Darier’s d. of the nail, desmoid tumor (with muscle involvement), epithelial sarcoma, erythema nodosum, fibrous papule of the nose, giant cell tumor of the tendon sheath, granuloma annulare, Herpesvirus infection, histiocytoma variant of dermatofibroma, histiocytosis X, histoplasmosis, histoplasmosis (African), infarcted lipoma, kala-azar, lichen nitidus, leiomyosarcoma, malignant fibrous histiocytoma, metastatic Crohn’s d., multicentric reticulohistiocytosis, mycetoma, NLD, neurofibroma, neurothekioma, palisaded encapsulated neuroma, paracoccidiodomycosis, peripheral ossifying fibroma, phaeohypomycosis, pseudoepitheliomatous hyperplasia, schwannoma, sclerosing lipogranuloma, soft tissue melanoma, sporotrichosis, synovial sarcoma, Talwin injection, tertiary lues, tuberculosis
giant cells, floret type
giant cell fibroblastoma, lepromatous leprosy, pleomorphic lipoma
giant cells, foreign body
actinomycetoma, chronic folliculitis, deep folliculitis eosinophilic cellulitis, juvenile xanthogranuloma, keratoacanthoma, lipodystrophy, lymphogranuloma venereum, necrobiotic xanthogranuloma, nevus sebaceous, nodular vasculitis, ochronosis, peripheral giant cell granuloma, pilomatrixoma, pityrosporon folliculitis, post-steroid fat necrosis, proliferating trichilemmal tumors, subcutaneous fat necrosis
giant cells, Langerhan’s
leprosy, leishmaniasis, lymphogranuloma venereum, sarcoidosis, tuberculoid leprosy
giant cells, osteoclast
giant cell malignant fibrous histiocytoma, nodular fasciitis
giant cells, Touton type
dermatofibroma, DFSP, diffuse normolipemic plane xanthoma, histiocytoma, histiocytoma variant of dermatofibroma, histiocytosis X, juvenile xanthogranuloma, necrobiotic xanthogranuloma with paraproteinemia, papular xanthoma, progressive nodular histiocytosis, xanthoma disseminatum, xanthomatous Hand-Schòller-Christian d.
giant melanosome
Albright’s s., Becker’s melanosis, café-au-lait spots, Chediak-Higashi s., lentigo simplex, lentiginosis profusa, LEOPARD s., melanocytic nevi, nevus spilus, normal skin
globi Mycoplasma leprae-containing secondary lysosomes within macrophages; lepromatous leprosy 
gossamer strandsthin fibrous strands; PMLE 
grains
cells in stratum corneum with small pyknotic nuclei surrounded by shrunken eosinophilic cytoplasm; Darier’s d., Hailey-Hailey d., mycetoma, transient acantholytic dermatosis, warty dyskeratoma
granular cell degeneration
see epidermolytic hyperkeratosis
granular cell layer, decreased
AK, Bowen’s d., clear cell acanthoma, confluent & reticulated papillomatosis of Gougerot & Cartedeau, harlequin fetus, ichthyosis vulgaris, pilar cyst, proliferating trichellemmal cyst, psoriasis
granular cell layer, increased
angiofibroma, epidermolytic hyperkeratosis, intraepidermal epithelioma, keratosis palmaris et plantaris, lamellar ichthyosis, lichen planus (focal), nevus sebaceous, perforating disorder of renal disease, pseudoepitheliomatous hyperplasia, Refsum’s d., seboacanthoma, Spitz nevus, wart, X-linked recessive ichthyosis
granular degeneration
see epidermolytic hyperkeratosis
granules
matted colonies of filamentous organisms; characterized by color

black: Madurella grisea, Exophilia jeanselmei, Madurella mycetomatis
red: Actinomadura pelletieri
white/yellow: Actinomyces israelii, Botryomycosis, Nocardia asteroides, Pseudallescheria boydii

also see sulfur granules
granuloma, foreign body
aluminum, asbestos, beryllium, calcium, carbon, isocyanates, metal, mineral oil, paraffin, quartz, ruptured follicular cyst, silica, silicon, spines, splinter, suture, talcum, tattoo, titanium, urate, wood, zirconium
granuloma, necrotizing
allergic granulomatosis, Wegener’s granulomatosis
granuloma, palisading
central necrobiosis & peripheral histiocytes, epithelioid cells, lymphocytes & giant cells; gout, GA, NLD, necrobiotic xanthogranuloma, pseudo-rheumatoid nodule, rheumatic fever nodule, rheumatoid nodule
granuloma, sarcoidal
epithelioid & giant cell granuloma; cheilitis granulomatosis, foreign body reactions, MCD, granulomatous rosacea, sarcoidosis, silica, zirconium
granuloma, tuberculoid
epithelioid & giant cell granuloma with cuff of lymphocytes; deep fungal, foreign body, leishmaniasis, leprosy, lupus miliaris disseminatous facei, protothecosis, rosacea, tertiary syphilis, tuberculoid leprosy, tuberculosis
grenz zone
uninvolved margin of dermis; acrodermatitis chronica atrophicans, actinic elastosis, B cell lymphoma, bullous mastocytosis, dermatofibroma, DFSP, granuloma faciale, lepromatous leprosy, leukemia cutis, lymphocytoma cutis, lymphoma cutis, metastatic lesions, Merkel cell carcinoma, neurothekioma, palisaded encapsulated neuroma, parapsoriasis en plaque, pseudolymphoma, sarcoidosis
ground glass cytoplasm
eosinophilic refractile-appearing cytoplasm of histiocytic cells; infantile self healing reticulohistiocytosis, multicentric reticulohistiocytosis, reticulohistiocytoma
Guarnieri bodies
keratinocyte eosinophilic intracytoplasmic inclusions; smallpox, vaccinia
hair germs
congenital vellus hamartoma, trichoepithelioma, trichoblastic fibroma, trichoblastoma
hair matrix
pilomatrixoma
hair pilar canal
trichoadenoma
hair shafts, longitudinal cleft
anhidrotic ectodermal dysplasia
Hansemann macrophages foamy eosinophilic macrophage containing Michaelis-Gutman bodies; malakoplakia
Hassal’s corpuscles
epithelial cells aggregated into concentric layers of keratinized cells; thymic cysts
Heinz bodies
denaturation of hemoglobin with formation of precipitates seen in peripheral RBC smears stained with methylene blue; associated with antimalarials, dapsone (in pts. with G6PD deficiency), fava beans, nitrofurantoin, oxidative stress, sulfonamides
hematopoesis, dermaladults; myelofibrosis neonates; ABO/Rh incompatability, hereditary spherocytosis, infection (CMV, coxsackie virus, rubella), stress, twin transfusion s.
hemosiderophage
macrophage or histiocyte containing phagocytized hemosiderin; chronic pigmented purpura, KS, stasis dermatitis
Henderson-Patterson bodies
globules of viral protein; molluscum contagiosum AKA molluscum bodies
herringbone pattern
DFSP, fibrosarcoma
HMB-45 vs. S-100
HMB-45 negative; dermal nevus cells, desmoplastic melanoma, neurotropic melanoma
S-100 negative; blue nevi
hob nailing
endothelial cell projection into vascular lumina; angiolymphoid hyperplasia with eosinophilia, angiosarcoma, Dabska tumor, retiform hemangioendothelioma, targetoid hemosiderotic hemangioma
Homer-Wright rosettes
concentrically arranged tumor cells; Merkel cell carcinoma, neuroblastoma (metastatic)
horn cyst
seborrheic keratosis, SCC, trichoepithelioma
horn pearls
see squamous pearls
hot spots
aggregates of transformed cells in UV-induced neoplasia
Huygens’ effect
condenser of microscope defocused to obtain a partial phase effect
hyalin bodies
see colloid bodies
hyalin globulesextra- and intra-cellular PAS+ masses; Kaposi sarcoma 
hydropic degeneration
basal cell degeneration with vacuole formation; dermatomyositis, discoid lupus, erythema dyschromicum perstans, EM, fixed drug eruption, lichen planus, lichen sclerosis et atrophicus, poikiloderma atrophicans vasculare, poikiloderma congenitale, SCLE, SLE AKA liquefaction degeneration, vacuolar degeneration
hypergranulosis
epidermal nevus, epidermolytic hyperkeratosis, LP, LSC, verruca vulgaris, x-linked ichthyosis
hypogranulosis
ichthyosis vulgaris, normal mucous membrane, psoriasis
immune complexes (perivascular)
bowel bypass s., cryoglobulinemia, drug reaction, EED, erythema nodosum leprosum, erythropoietic protoporphyria, EM, granuloma faciale, leukocytoclastic vasculitis, Lucio phenomenon, lupus profundus, meningococcemia, NLD, nodular vasculitis, polyarteritis nodosa, PCT, Schamberg’s d., serum sickness, urticarial vasculitis, Wegener’s granulomatosis 
immunofluorescence, indirect
pemphigus foliaceous 70%, bullous pemphigoid >70%, HG factor 25%, linear IgA disease <25%
immunofluorescence, indirect (intercellular)
blood group A & B antibodies, bullous pemphigoid, burn, cicatricial pemphigoid, myasthenia gravis, pemphigus vulgaris, penicillin reaction, lichen planus, SLE, TEN
inclusions, intracytoplasmic
molluscum contagiosum, orf, paravaccinia (milker’s nodules), smallpox, vaccinia
inclusions, intranuclear
coxsackie virus, enterovirus, herpesvirus, human papillomavirus, orf, paravaccinia, rubeola
Indian filing
linear infiltration of cells; adenocarcinoma, breast cancer metastasis, epithelioid hemangioendothelioma, granuloma annulare, lymphocytic lymphoma, lymphocytoma cutis, lymphoma, pseudolymphoma
infiltrate, eosinophilic
allergic granulomatosis, angioedema, angiolymphoid hyperplasia with eosinophilia, autoimmune progesterone dermatitis, BP, eosinophilic cellulitis, eosinophilic spongiosis, eosinophilic tongue ulcers, eosinophilic pustulosis of the scalp in children, erythema toxicum neonatorum, granuloma faciale, halogenodermas, herpes gestationis, hypereosinophilic s., infestations, insect bite, Ofuji’s d., papular dermatitis of pregnancy, PUPPP
intracellular hyaline globules
Kaposi’s sarcoma
intraepidermal spread
Bowen’s d., epidermotropic metastatic melanoma, epidermotropic metastatic disease, hidroacanthoma simplex, Paget’s d., seborrheic keratosis, superficial spreading malignant melanoma
'invisible' dermatoses anetoderma (absent elastin), argyria (sweat gland), dermatophytoses (may not have inflammation), macular amyloid (pigment incontinence), mastocytosis, ichthyosis vulgaris (decreased or absent granular layer), TMEP, urticaria (eos and lymphocytes), vitiligo (need melanin stain),
iron deposits
hemochromatosis, nevus sebaceous, progressive nodular histiocytoma, xanthoma disseminatum
jigsaw puzzle-like
cylindroma
Kamino bodies
eosinophilic aggregations of type IV collagen; epithelioid cell nevus, melanoma, spindle cell nevus, Spitz nevus (60-88%)
karyorrhexis
nuclear fragmentation with formation of basophilic nuclear dust; leukocytoclastic vasculitis
keratin pearls
see squamous pearls
keratinosome body
see Odland body
knife marks
seen on a slide; silica granulomas
Kogoj, spongiform pustule of
intraepidermal neutrophil aggregate within sponge-like area; acrodermatitis continua of Hallopeau, candidiasis, dermatophytosis, geographic tongue, halogenodermas, impetigo, psoriasis, Reiter’s d., subcorneal pustular dermatosis
koilocyte
squamous cell with hyperchromic nuclei surrounded by perinuclear halo; HPV
Kulchitsky cells
endocrine cells with granular or pale pink cytoplasm; argentaffin gut cells; carcinoid
lacunae
splits in basal cell layer; Darier’s d. AKA intraepidermal blisters
lacunar cells
immunoglobulin cell with single hyperlobated nucleus with small nucleoli, cytoplasm retracts in formalin fixed tissue with resultant clear space around cell; Hodgkin’s lymphoma (nodular sclerosis variant)
lamellar body
see Odland body
Langerhan cells, decreased
HIV, old age, PUVA therapy
Langerhan cells, increased
early lichen planus, mycosis fungoides
Langerhan giant cells
multinucleate histiocytic giant cell with peripheral nuclei; foreign body reactions, hypersensitivity reactions
Leishman bodies
epidermal inclusions in leishmaniasis
leukocytoclasis
karyorrhexis and neutrophil degeneration with nuclear dust; leukocytoclastic vasculitis
lichenoid infiltrate
GVH, lichenoid drug eruption, lichenoid keratosis, lichen planopilaris, LP, LE, poikiloderma vasculare atrophicans
lipid vacuoles
Refsum’s d., Chanarin-Dorfman s.
lipomembranous change  lipomembranes around fat; eosinophilic protein with a feathery appearance; lobular panniculitis with focal macrophage infiltration and fibrosis. PAS+ and elastic stain +; LE panniculitis, morphea
Lipshutz bodies/granules
inclusion bodies in cytoplasm of infected ballooned epithelial cells; HSV, molluscum contagiosum (pox virus)
liquefaction degeneration
see hydropic degeneration
Luse bodies
long collagen fibers; Hodgkin’s lymphoma, lymphoproliferative disease, multicentric reticulohistiocytosis, neural tumors
lymphocytes, satellite
lymphocytes in close apposition to dyskeratotic keratinocytes; GVH d.
lymphoid follicles, reactive
angiolymphoid hyperplasia with eosinophilia, Castleman d., dermatofibroma, desmoplastic malignant melanoma, epulis fissuratum, Kimura d., lupus profundus, lymphoma, morphea, necrobiosis lipoidica, lupus panniculitis, necrobiotic xanthogranuloma
lymphoid follicles with germinal centers
ALHE, BCC, Castleman d., cutaneous lymphoid hyperplasia, inflammatory pseudotumor of the skin, Kimura’s d., marginal zone lymphoma, morphea
lymphophagocytosis
cytophagic histiocytic panniculitis, malignant histiocytosis, sinus histiocytosis with massive lymphadenopathy
macromelanosomes
see melanosomes, giant
Mallory body
finding in scarlet fever
mast cells
androgenic alopecia, atopic dermatitis, keloid, lichen planus, lichen simplex chronicus, lupus erythematosus, mastocytoma, neurofibroma, spindle cell lipoma, synovial sarcoma, trichogerminoma
Max Joseph cleft/space
hydropic degeneration of basal layer leading to epidermal separation; lichen planus
Medlar bodies
intermediate vegetative form of chromoblastomycosis (pathognomonic) AKA copper pennies, muriform cells
Meischer’s microgranuloma
small histiocytes radially arranged around a central cleft; erythema nodosum AKA Meischer’s radial granuloma
Meissner corpuscle

melanin granules
café-au-lait spots, eruptive nevi, generalized lentigines, metastatic malignant melanoma, xeroderma pigmentosum
melanin granules, giant
Albright’s s., melanocytic nevi, multiple lentiginosis s. neurofibromatosis (café-au-lait macules), nevus spilus
melanin macroglobules
found in: Becker’s nevus, café-au-lait spots (neurofibromatosis), Chediak-Higashi s., generalized melanosis, Hermansky-Pudlak s., LEOPARD s., lentigo simplex, lentigo maligna, leukoderma, melanoma, nevi, nevus spilus, NF, post PUVA lentigines, tinea versicolor, X-linked ocular albinism, XP
melanin, decreased
albinism, hypopituitarism, monobenzylether of hydroquinone, piebaldism, Tietze’s s., Vogt-Koyanagi-Harada s.
melanin, increased
Addison’s d., Albright’s d., Becker’s melanosis, bleomycin administration, busulfan, café-au-lait macules, carbon baby s., chlorpromazine administration, Cronkhite-Canada s., Dowling Degos d., doxorubicin, dyskeratosis congenita, ephelides (or decreased), Fanconi’s s., fixed drug eruption, gold administration, hemochromatosis, labial melanotic macule, lamprene administration, lentigo simplex, mechlorethamine, melanosis diffusa congenita, melasma, minocycline administration, neurofibromatosis, nevus spilus, POEMS s., Peutz-Jeghers s., post-inflammatory hyperpigmentation, reticulate acropigmentation of Kitamura, senile lentigo, silver exposure, solar lentigo, tanning, topical psoralens, topical nitrogen mustard, 5-FU
melanocytes, absent
chemical depigmentation, halo nevi, piebaldism, pinta, traumatized area, vitiligo, Vogt-Koyanagi-Harada s., Waardenburg’s s., Wolf’s s., XP
melanocytes, increased
Addison’s d., Becker’s melanosis, café-au-lait macules in neurofibromatosis, centrofacial neurodysraphic lentiginosis, lentigo maligna, lentigo simplex, LEOPARD s., mechlorethamine, melasma, Moynahan’s s., nevus spilus, Peutz-Jeghers s., reticulate acropigmentation of Kitamura, segmental lentiginosis, senile lentigo, Soto’s s., tanning
melanocytes, normal
Addison’s d., albinism, ash leaf macule of tuberous sclerosis, Chediak-Higashi s., ephelides, labial melanotic macule, melanotic macules of Albright’s s., nevus depigmentosus, PKU, Peutz-Jeghers s., sarcoidosis, senile lentigo, Ziprokowski-Margolis s.
melanocytes, reduced
alopecia areata, ash leaf macule of tuberous sclerosis, ephelides, halo nevus, idiopathic guttate hypomelanosis, incontinentia pigmenti achromians, leprosy, lichen planus, Menkes s., pityriasis alba, post-inflammatory hypopigmentation, Vagabond’s d., Ziprokowski-Margolis s.
melanophage
phagocytized melanin in histiocyte or macrophage; blue nevus, fixed drug eruption, lichen planus, melanoma, post-inflammatory hyperpigmentation, seborrheic keratosis
melanosome macrocomplexes
melanosomes sequestered in lysosomes; seborrheic keratoses
melanosomes, giant (macromelanosomes)
unusually large melanin granule aggregations; Albright’s s. (rare), alcoholic liver d., Becker’s melanosis, café-au-lait macules, Chediak-Higashi s., Hermansky-Pudlak s., lentigines, LEOPARD s., neurofibromatosis, nevus spilus, normal skin, piebaldism, primary biliary cirrhosis, vitiligous achromia with malignant melanoma, XP, XLR ocular albinism
membrane coating granules
see Odland bodies
meridional array
quadrennial structure of B-pleated sheet; amyloidosis
Michaelis-Gutman bodies
intracytoplasmic calcified basophilic bodies in phagolysosomes of von Hansemann cells; malakoplakia  AKA calcospherules
Mickulicz cells
large pale foamy histiocytes containing clumps of encapsulated Klebsiella bacteria; rhinoscleroma
microabscess (papillary)
bullous LE, dermatitis herpetiformis
molluscum bodies
globules of viral protein; molluscum contagiosum AKA Henderson-Patterson bodies
morulae
intracellular inclusion bodies; Ehrlichiosis
mucinoses
primary; acquired digital fibrokeratoma, acral persistent papular mucinosis, connective tissue disease, cutaneous mucinosis of infancy, focal mucinosis, granuloma annulare, lichen myxedematosus, myxedema (generalized & localized) papular mucinosis, myxoid cyst, plaque-like cutaneous mucinosis, melanoma (myxoid melanoma), self healing juvenile cutaneous mucinosis
secondary; BCC, Degos’ d., etretinate therapy, LE, palisading granulomas, PUVA therapy, reticular erythematous mucinosis, skin cancers, toxic oil s.
mucous secretory granules
adenoid cystic carcinoma, apocrine carcinoma, apocrine cystadenoma, apocrine hidrocystoma, chondroid syringoma, clear cell hidradenoma, hidradenoma papilliferum, metastatic tumor of glandular differentiation, mucinous carcinoid, mucinous carcinoma, Paget’s d., syringocystadenoma papilliferum
mulberry cells
1. hibernoma  2. glycolipid in urine sediment; Fabry disease  3. protothecosis
multifocal tumors
Bowen’s d., Paget’s d., recurrent tumors, sebaceous carcinoma
multinucleated giant cells
multinucleated keratinocytes; HSV infection
Munro microabscess
subcorneal abscess formed by neutrophils; impetigo, psoriasis, Reiter’s s., seborrheic dermatitis
muriform cells
intermediate vegetative form of chromoblastomycosis (pathognomonic) AKA copper pennies, Medlar bodies
myofibroblasts
cranial fasciitis of infancy, dermatofibroma, desmoid, Dupuytren’s contracture, fibroma of the tendon sheath, fibrous hamartoma of infancy, infantile myofibromatosis (congenital generalized fibromatosis), infantile digital myofibroblastoma (infantile digital fibromatosis), keloids, malignant fibrous histiocytoma, nodular fasciitis (pseudosarcomatous)
myxoid diseases
see mucinoses
n-alkanes
epidermolytic hyperkeratosis, lamellar ichthyosis
necrobiosis
necrosis leading to homogenization of dermal collagen; GA, NLD, NXG, rheumatoid nodule
necrotic nidus
insect bites
needle shaped clefts in subcutaneous fat
post-steroid panniculitis, sclerema neonatorum, subcutaneous fat necrosis of the newborn
neuron specific enolase
BCC, epithelioid sarcoma, Merkel cell carcinoma
neurosecretory granules
Merkel cell carcinoma
neurotropism
congenital nevi, desmoplastic malignant melanoma, microcystic adnexal carcinoma, neurotropic malignant melanoma
neutrophilic micro abscesses, intraepidermal
candidiasis, deep fungal, granuloma inguinale, halogenoderma, impetigo, psoriasis, tuberculosis verrucosa cutis
neutrophilic lysosomes, enlarged
Chediak-Higashi s.
neutrophils, dermal
Behçet’s s., cellulitis, familial Mediterranean fever, bowel associated dermatitis-arthritis s., neutrophilic eccrine hidradenitis, pyoderma gangrenosum, rheumatoid nodule, Sweet’s s.
neutrophils, epidermal
candidiasis, infantile acropustulosis, impetigo herpetiformis, neutrophilic spongiosis, pustular psoriasis, Reiter’s s., subcorneal pustular dermatosis (Sneddon-Wilkinson), transient neonatal pustular melanosis
neutrophils, intraepithelial
acropustulosis of infancy, Candida infection, dermatophytes, gonococcemia, halogenodermas, impetigo, keratoacanthoma, miliaria, Reiter’s s., pinta, psoriasis, Sneddon-Wilkinson s., sporotrichoid leishmaniasis, secondary syphilis, toxic shock s., yaws
neutrophils, perivascular
cellulitis, erysipelas, neutrophilic urticaria, Still’s d., Sweet’s s.
nuclear dust
debris from neutrophils; leukocytoclastic vasculitis, Sweet’s s.
nuclei, blunt ended
leiomyoma
nuclei, cerebriform
atypical T lymphocyte nuclei; CTCL, Sezary s.
Odland bodies
EM; oval bodies in spinous layer
orthokeratosis
non-nucleated stratum corneum; ichthyosis vulgaris, lichen planus, verruca plana
osseous metaplasia
chondroid syringoma, epithelioid sarcoma, nevi, penile fibromatosis, pilomatrixoma
ossification
BCC, calcifying epithelioma of Malherbe, peripheral ossifying fibroma, Peyronie’s d.
osteoblasts
fibro-osseous pseudotumor of the digits (osteoblasts)
osteoclasts
fibro-osseous pseudotumor of the digits, giant cell tumor of tendon sheath, giant cell epulis, giant cell variant of malignant fibrous histiocytoma
osteoid formation
aponeurotic fibromatosis, epithelial sarcoma, fibrosarcoma, giant cell malignant fibrous histiocytoma, malignant mixed tumor, malignant schwannoma, MFH-giant cell type, ossifying fibroma, peripheral giant cell granuloma, peripheral giant cell granuloma, peripheral ossifying fibroma, peripheral proliferative myositis (myositis ossificans)
osteoma cutis (secondary)
acne vulgaris, AK, AFX, BCC, bronchogenic carcinoma (metastatic), chondroid syringoma, chondroma, chronic venous insufficiency, dermatofibroma. dermatomyositis, desmoid tumor, desmoplastic melanoma, epidermal nevus, folliculitis, Gardner’s s., hemangioma, infundibular cyst, lipoma, LE, morphea, myositis ossificans, neurilemmoma, pilar cyst, pilomatrixoma, pyogenic granuloma, scleroderma, syphilis, trauma, trichoepithelioma
Paget cells
large round cells with large nuclei & abundant pink cytoplasm; Paget’s d.
Pagetoid spread
upward spread of cells in the epidermis: melanoma (melanocytes); Paget d., sebaceous carcinoma
panniculitis
cellular infiltrates (atypical); leukemia, lymphoma
cellular infiltrates(lymphoplasma); connective tissue panniculitis, dermatomyositis,
lipoatrophy, necrobiosis lipoidica
crystal formation; subcutaneous fat necrosis, sclerema neonatorym, poststeroid panniculitis, oxalosis, gout
cytophagocytosis; cytophagic histiocytic panniculitis
ghost cells/saponification; pancreatic panniculitis
hyalinization/lymphoplasma cellular infiltrates; lupus panniculitis
palisading granulomas; granuloma annulare, rheumatoid nodule, necrobiosis lipoidica
septal sclerosis; morphea profunda, scleroderma, eosinophilic fasciitis
sclerosing lipogranuloma; implanted lipids
vasculitis; small vessel vasculitis, polyarteritis, thrombophlebitis
vessel calcification; calciphylaxis
vessel thrombosis; coagulopathy, cryoprecipitate
panniculitis
cutaneous periarteritis nodosa, cytophagic histiocytic panniculitis, Rothmann-Makai s., sarcoidosis, scleroderma, sclerosing lipogranuloma
panniculitis, lobular
a-1 antitrypsin deficiency, blunt trauma, cold, connective tissue panniculitis, erythema induratum, infection, leukemia, lipodystrophy, lupus profundus, pancreatic disease, sclerema neonatorum, steroid injection, subcutaneous fat necrosis of the newborn, Weber-Christian
panniculitis, septal
infections: blastomycosis, campylobacter colitis, cat-scratch d., chlamydial, coccidioidomycosis, gonorrhea, histoplasmosis, infectious mononucleosis, leprosy, lymphogranuloma inguinale, ornithosis, salmonellosis, shigellosis, streptococcal, syphilis, trichophytosis (deep), tuberculosis, yersiniosis
malignancies: carcinoma, Hodgkin’s d., leukemia, sarcoma
medications: bromine, iodine, OCPs, penicillin, phenacetin, pyritinol, sulphathiazole
miscellaneous: Behçet’s d., Crohn’s d., PAN, pregnancy, Sweet’s s., ulcerative colitis
papillary endothelial hyperplasia
cavernous hemangioma, pyogenic granuloma, venous lake, capillary aneurysm, multiple superficial phlebectasia, lymphangiomas, angiolymphomatoid hyperplasia with eosinophilia
papillary mesenchymal bodies
epithelial structures resembling hair papillae; trichoepitheliomas
papillomatosis
elongation of epidermis & papillary dermis; acanthosis nigricans, seborrheic keratosis, verruca
parakeratosis, alternating
retained nuclei in stratum corneum; ILVEN, psoriasis, pityriasis rubra pilaris
parakeratosis, mounded
chronic spongiotic dermatitis, guttate psoriasis, ILVEN, PR, seborrheic dermatitis, xerosis
parakeratosis, shoulderparakeratotic aggregations at follicular infundibula; seborrheic dermatitis
parasitized histiocytes
American trypanosomiasis, granuloma inguinale, histoplasmosis, leishmaniasis, rhinoscleroma, toxoplasmosis (within keratinocytes)
Paschen bodies
see Guarnieri bodies
"patchy L's"
patchy lympocyte collections; arthropod, CLL, EAC, PMLE, SLE, Syphilis
pattern recognition (instant)
accessory nipple, actinomycosis (eosinophilic sulfur granule), angiokeratoma, calciphylaxis, capillary angioma, clear cell acanthoma, CNCH, DF, eruptive xanthoma, fibroepithelioma, granular cell tumor, harlequin fetus, hibernoma (mulberry cells), molluscum contagiosum (Henderson-Patterson bodies), keratoacanthoma, mucinous carcinoma (aggregates of mucin), neurothekioma, onchocerciasis (aggregate of worms), Paget’s, porokeratosis (coronoid lamellae), PXE (dermal dilapidation-calcium), venous lake, verrucae, verruca plana, xanthelasma
Pautrier’s microabscess
aggregate of atypical lymphocytes in epidermis with clear surrounding space; contact dermatitis, drug eruption, leukemia cutis, mycosis fungoides, PLEVA, PR, poikiloderma vasculare atrophicans
perineural invasion
adenoid cystic carcinoma, BCC, blue nevi, congenital nevi, desmoplastic melanoma, keratoacanthoma, metatypical BCC, microcystic adnexal carcinoma, porocarcinoma, Spitz nevi, Spitz variant of the minimal deviation melanoma
pertinax bodies
acidophilic masses; old nails
physaliferous cells
chordoma
pigment incontinence
melanin deposition; erythema dyschromicum perstans, EM, fixed drug eruption, IP, lentigo, lichen planus, lichenoid reaction, LE, poikiloderma, post-inflammatory hyperpigmentation
plasma cells
AK, angiomatoid MFH, BCC, connective tissue disease, desmoplastic malignant melanoma, distinctive exudative discoid and lichen eruption, folliculitis, foreign body granuloma, granuloma inguinale, Kaposi’s sarcoma, keratosis lichenoides chronica, lichen sclerosis, lues, LE, MF, NLD, nodular amyloid, papillary adenoma of the nipple, papillary syringoadenoma, periorificial inflammatory infiltrates, plasma cell vulvitis,  plasma cell cheilitis, plasmacytoma, polyarteritis nodosa, rhinoscleroma, scalp and midline areas (normal), secondary syphilis, SCC, scleroderma, syringocystadenoma papilliferum, Zoon balanitis
pleated sheets
bilayered lipids in lamellar bodies in the cytoplasm of keratinocytes
polaroscopic positive
erythema elevatum diutinum, dermatofibroma, Fabry’s d., Hand-Schuller-Christian d., juvenile xanthogranuloma, normolipemic plane xanthoma, plane xanthoma, sclerema neonatorum, subcutaneous fat necrosis of the newborn, Tangier’s d., tuberous xanthoma, xanthelasma
popcorn nuclei
irregular multilobed nuclei; lymphocytic or histiocytic cells in Hodgkin’s d. (nodular lymphocyte-predominant)
promontory sign
normal adnexal structures and blood vessels protruding into newly formed blood vessels; kaposi sarcoma
psammoma bodies
laminated hyalin with calcifications; choroid plexus, cutaneous endometriosis, endosalpingosis, juvenile xanthogranuloma, mammary intraductal papilloma, meningioma, nevocellular nevi, nevi, ovarian cancer, pineal gland, pituitary gland, thyroid cancer-papillary type
pseudo Pautrier’s microabscesses
chronic actinic dermatitis
pseudocarcinomatous hyperplasia
see pseudoepitheliomatous hyperplasia
pseudoepitheliomatous hyperplasia
irregular proliferation of epidermis into dermis; atypical mycobacteria, atypical fibroxanthoma, bacillary angiomatosis, blastomycosis, bromoderma, BCC, burns, cat scratch d., chromoblastomycosis, coccidioidomycosis, cutaneous amebiasis, condyloma lata, Darier’s d., deep fungal infections, ecthyma contagiosum, epidermal inclusion cyst, keratoacanthoma, grease gun granuloma, granuloma inguinale, granular cell tumor, gumma, halogenodermas, hidradenitis suppurativa, inflammatory papillary hyperplasia, iododerma, keratoacanthoma, leishmaniasis, lichen planus, lupus vulgaris, lymphogranuloma venereum, malignant melanoma, mycobacterial infection, necrotizing sialometaplasia, osteomyelitis, paracoccidiodomycosis, pemphigoid vegetans, pemphigoid vegetans (Neumann type), phaeohyphomycosis, pigmented spindle cell nevus, podophyllin application, proliferating trichilemmal cyst, prurigo nodularis, pseudoepitheliomatous keratotic and micaceous balanitis, pyoderma gangrenosum, pyoderma vegetans, scrofuloderma, Spitz nevus, sporotrichosis, syphilis, tularemia, ulcers (chronic)
pseudohorn cysts
seborrheic keratoses
pseudorosette
Merkel cell carcinoma
pseudorosette (Homer-Wright)
neuroblastoma
pseudovascular spaces
compound nevi
psoriasiform epidermal hyperplasia
usual: acrodermatitis enteropathica ichthyosis linearis circumflexa, ILVEN, lamellar ichthyosis, lichen simplex chronicus, pellagra, pityriasis rubra pilaris, prurigo nodularis, psoriasis, Reiter’s s.
frequent: contact dermatitis, MF, nummular dermatitis, PR, seborrheic dermatitis, syphilis
occasional: candidiasis, dermatophytosis, geographic tongue, incontinentia pigmenti, necrolytic migratory erythema, scabies
pustule, eosinophilic
eosinophilic folliculitis, eosinophilic pustulosis of the scalp in children, erythema toxicum neonatorum, halogenodermas, incontinentia pigmenti, keratoacanthoma, pemphigus vegetans
pustule, neutrophilic
acral pustulosis of infancy, acrodermatitis of Hallopeau, impetigo, pustular psoriasis, subcorneal pustular dermatosis (Sneddon-Wilkinson), Reiter d., transient neonatal pustular melanosis
pustule, spongiform
Candida, geographic tongue, psoriasis
pustule, subcorneal
candidiasis, dermatophytosis, impetigo, miliaria crystallina, pemphigus erythematosus, pemphigus foliaceus, psoriasis, pyoderma gangrenosum, staphylococcal scalded skin s., subcorneal pustular dermatosis, toxic erythema of the newborn
pustulo-ovoid bodies of Milian
round eosinophilic cytoplasmic granules; granular cell tumor
radiation fibroblasts
radiotherapy
railroad track
appearance of arrangement of bacteria (Haemophilus ducreyi); chancroid
Reed-Sternberg cells
mirror image binucleated lymphocytes (classic finding infrequent); B or T-cell Hodgkin’s lymphoma, lymphomatoid papulosis, pseudolymphoma
Rocha-Lima bodies
pink-purple cytoplasmic inclusions in endothelial cells; Bartonella bacilliformis (Oroya fever/verruga peruana)
round cell tumors, small
embryonal and alveolar rhabdomyosarcoma, Ewing sarcoma, melanoma, Merkel cell carcinoma, neuroblastoma, oat cell lung carcinoma, small cell osteosarcoma
Russell bodies
copious homogenous eosinophilic immunoglobulin within plasma cells; chancroid, hidradenitis suppurativa, mucocutaneous leishmaniasis, rhinoscleroma, syphilis
satellite cell necrosis
lymphocytes attached to dead keratinocytes; erythema multiforme, GVHD, TEN
satellitosis
acute GVHD, lichen planus
saw tooth epidermis
serrated appearance of epidermis; lichen planus
Schaumann bodies
calcified inclusions from degenerated lysosomes in macrophages & histiocytes; berylliosis, sarcoid, tuberculosis
school of fish
appearance of arrangement of bacteria (Hemophilus ducreyi); chancroid
sclerosis
increased collagen, decreased fibroblasts; morphea, necrobiosis lipoidica, radiodermatitis (chronic), scleroderma
sclerotic bodies
Medlar bodies; chromoblastomycosis
sclerotic stroma
chondroid syringoma, ductal adenocarcinoma, sclerosing BCC, syringoma, trichoepithelioma
scutula
hyphal bodies; favus
secretion, decapitation
apocrine cystadenoma
Sezary cells
atypical T-cells in peripheral smear with cerebriform nuclei; actinic reticuloid, atopic dermatitis, B-cell lymphoma, BCC, chronic dermatoses, DLE, LP, lymphomatoid papulosis, MF, normal persons, parapsoriasis en plaques, PLEVA, Sezary s. (must be 5-10% of total WBC), solar keratosis, psoriasis
shadow cells
pale eosinophilic cell with central clearing & absent nucleus; fat necrosis, pilomatricoma AKA ghost cell
ship pilot’s wheel
round yeast cells with narrow necked buds; paracoccidiodomycosis
signet ring cells
adenocarcinoma (metastatic), BCC, breast carcinoma (metastatic), melanocytic nevus, melanoma, MF, SCC
spaghetti & meatballs
hyphal & yeast elements observed in KOH preparation; Pityrosporum ovale (tinea versicolor)
Splenodre-Hoeppli phenomenon
PAS positive amorphous eosinophilic material surrounding granules of clumped bacteria; actinomycosis, botryomycosis, entomophthoromycosis
spongiform pustules
Candida, geographic tongue, psoriasis
spongiosis
allergic vesicular id eruption, atopic dermatitis, contact dermatitis, eczematous dermatitis, pityriasis rosea, PMLE, pompholyx, vesicular dermatophytosis
spongiosis, eosinophilic
intracellular epidermal edema with eosinophils; allergic contact dermatitis, arthropod bite, bullous pemphigoid, cicatricial pemphigoid, dermatitis herpetiformis, drug eruption, eczematous dermatitis, eosinophilic cellulitis (Well’s s.), epidermolytic epidermolysis bullosa, erythema toxicum neonatorum, erythromelanoderma, herpes gestationis, hypereosinophilic s., incontinentia pigmenti (vesicular stage), milker’s nodule, pemphigus foliaceus, pemphigus vegetans, pemphigus vulgaris, polycythemia rubra vera, porokeratosis of Mibelli, scabies, subcorneal pustular dermatosis
squamatization
hydropic basal cell layer degeneration; GVH d., lichen planus, lupus erythematosus
squamous eddies
round onion-like aggregate of eosinophilic keratinocytes; AK, keratoacanthoma, seborrheic keratosis (irritated), SCC, warty dyskeratoma
squamous pearls
round garlic clove-like aggregate of eosinophilic keratinocytes; SCC, SK
square shoulder biopsy
scleroderma
stag-horn appearance
tumor cdells surrounding multiple thin-walled blood vessels; hemangiopericytoma
starry sky pattern
Burkitt’s lymphoma
stellate abscesses
cat-scratch disease, fungal infections, lymphogranuloma venereum, melioidosis, sporotrichosis, tularemia
storiform pattern
whirling cellular pattern around acellular zones (occasionally around small blood vessels); DFSP
substance P amyloid
normal substance of serum & elastic fibers
sulfur granules
matted colonies of filamentous organisms exuded from skin sinuses; actinomycosis, botryomycosis, mycetoma
sunburn cells
dyskeratotic keratinocytes; actinic skin, AK, SCC
swarm of bees
peribulbar lymphocytic infiltrate; alopecia areata
sweat gland necrosis
barbiturates, gas gangrene (clostridia), hypoxia, pressure
T cell clonality
follicular mucinosis, pagetoid reticulosis, parapsoriasis, MF
T cells
TH cells; annular elastolytic granuloma, erythema nodosum leprosum, pseudolymphoma, tuberculoid leprosy    TS cells; lepromatous leprosy
telangiectasias
Osler-Weber-Rendu s., trichodiscomas
tesselated pattern
appear like a tile floor; urticaria pigmentosa (mast cells separated)
tingible body macrophages
large macrophages containing fragmented basophilic nuclear & cytoplasm fragments of degenerated lymphoid cells; pseudolymphoma
tombstoning
basal cells of blister floor protrude into blister; pemphigus vulgaris
Touton giant cells
histiocytic multinucleated giant cell with ring of nuclei; JXG, xanthogranuloma, xanthoma
transepidermal elimination
calcinosis cutis, CNCH, chromomycosis, elastosis perforans serpiginosa (elastic fibers), granuloma annulare (collagen fibers), hidradenitis suppurativa (elastic fibers), Kyrle’s d., lichen nitidus, melanoma, NLD (collagen fibers), nevi, osteoma cutis, perforating disorder of renal disease (collagen fibers), perforating folliculitis (collagen & elastic fibers), pigmented spindle cell nevus, porokeratosis of Mibelli, PXE (altered elastic fibers), reactive perforating collagenosis-collagen, rheumatoid nodules, sarcoidal granuloma, Spitz nevus, vellus hair cysts
triglyceride crystals
sclerema neonatorum, subcutaneous fat necrosis
tuberculosis
bacilli; primary inoculation TB (+++), miliary TB (++/+), lupus vulgaris (rare), TB verrucosus cutis (rare), scrofuloderma (+), TB cutis orificialis (+++)
ulceration
atypical fibroxanthoma, BCC, DFSP, epithelioid sarcoma (superficial type), malignant melanoma, papillary adenoma of the nipple, SCC
vascular plugging
antiphospholipid s., coumadin necrosis, cryoglobulinemia, DIC, heparin necrosis, mixed cryoglobulinemia, paroxysmal nocturnal hemoglobinuria, protein C & S deficiency, purpura fulminans, TTP
vacuolar degeneration
see hydropic degeneration
vasculitis, lymphocytic
angiocentric lymphoma, drug eruptions, lupus, lymphomatoid papulosis, pernio (chilblains), PLEVA, pyoderma gangrenosum
vase-like shape, mononuclear cells
aggregation of mononuclear cells resembling Pautrier’s microabscesses; spongiotic dermatitis (not MF)
Verocay bodies
parallel rows of nuclei surrounding homogenous eosinophilic material; neurilemmoma (Antoni type A area), schwannoma
vesicle, subepidermal teardrop shape
pemphigoid gestationis
villus
prominent dermal papilla within a blister cavity; Darier’s d., pemphigus, warty dyskeratoma
vimentin
chondroblasts, endothelium, fibroblasts, mesothelium, sarcoma, smooth muscle cells, spindle cell SCC
Virchow cells
Mycobacterium leprae in lysosomes make foamy histiocytes; lepromatous leprosy AKA globi
von Hansemann cells
foamy eosinophilic macrophage containing Michaelis-Gutman bodies; malakoplakia
wedge shape
arthropod bite, PLEVA, PLC
Weibel-Pelade bodies
EM; electron dense rod-shaped organelles of parallel tubules found in endothelial cells, vascular tumors
Willemze Type A
LP with histiocytes
Willemze Type B
LP with lymphocytes
windblown appearance
epidermal architectural disarray; Bowen d.
zebra bodies
EM; lipid vacuoles with transverse membranes; Farber’s d., mucopolysaccharidosis
 

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