Dermatopathology

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

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

apoptotic 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

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

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

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

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

curvilinear bodies

cutaneous horn

conical hyperkeratotic papule; AK, BCC, SCC, SK, trichilemmoma, trichilemmal keratosis, verrucae

cytoid bodies

cytoplasmic inclusions, pleomorphic

multicentric reticulohistiocytosis

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

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

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

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

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

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

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

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

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

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

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

hot spots

aggregates of transformed cells in UV-induced neoplasia

Huygens’ effect

condenser of microscope defocused to obtain a partial phase effect

hyalin bodies

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

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

keratinosome 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

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.

Lipshutz bodies/granules

inclusion bodies in cytoplasm of infected ballooned epithelial cells; HSV, molluscum contagiosum (pox virus)

liquefaction 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

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

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

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

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

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.

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

parasitized histiocytes

American trypanosomiasis, granuloma inguinale, histoplasmosis, leishmaniasis, rhinoscleroma, toxoplasmosis (within keratinocytes)

Paschen bodies

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

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)

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

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

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, 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)

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

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

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

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

T_H cells; annular elastolytic granuloma, erythema nodosum leprosum, pseudolymphoma, tuberculoid leprosy    T_S cells; lepromatous leprosy

telangiectasias

Osler-Weber-Rendu s., trichodiscomas

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

vacuolar 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

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

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

zebra bodies

EM; lipid vacuoles with transverse membranes; Farber’s d., mucopolysaccharidosis