Slides

Question 1

Answer 1

Plexiform neurofibroma

Multiple nodules of neurofibroma as juxtaposed units throughout dermis and/or subcutis.

Question 2

Answer 2

Angioleimyoma

Well-circumscribed, subcutaneous or deep dermal solid nodule. Large interlacing bundles of plump spindle cells with ample eosinophilic cytoplasm, cigar-shaped nuclei and paranuclear vacuoles arranged around slit like or dilated blood vessels.

Question 3

Answer 3

Steatocystoma

Intradermal cyst lined by thin squamous epithelium. Compressed sebaceous glands in cyst wall. Wavy eosinophilic “shark tooth” crenulated cuticle.

Question 4

Answer 4

Pityriasis Lichenoides Chronica

Focal parakeratosis, scattered dyskeratotic cells in epidermis. Upper dermal sparse inflammation, mostly lymphocytes, sometimes with scattered melanphages. Focal vacuolar alteration at DEJ and dermal fibrosis. Red cell extravasation.

Question 5

Answer 5

Solar Lentigo

Club-shaped rete ridges with basal hyperpigmentation (puppy feet, dirty feet) in a background of solar elastosis. No confluence of single melanocytes or nests noted.

Question 6

Answer 6

Elastosis Perforans Serpiginosa

Epidermal perforation with extrusion of altered elastic fibers through defect in epidermis. Surrounding epidermis shows acanthosis and may appear to clutch the dermis. Increased elastic fibers in dermis near perforation. Bramble bush lumpy bumpy elastic fibers with lateral buds in penicillamine induced EPS.

Question 7

Answer 7

Erythema Elevatum Diutinum

Nodular, dense mixed infiltrate with neutrophils and admixed lymphocytes and plasma cells. Leukocytoclastic vasculitis may be seen. Fibrosis or lipid deposits in late lesions.Grenz zone +/-.

Question 8

Answer 8

Histoplasma Capsulatum

Intracellular cysts (2-4 microns), evenly distributed and surrounded by pseudocapsule in a background of granulomatous inflammation.

Question 9

Answer 9

Seborrheic Keratosis

Epidermal acanthosis, papillomatosis with overlying hyperkeratosis and focal parakeratosis. Broad sheets of small to medium sized basaloid cells with squamoid differentiation are separated by scattered psedohorn cysts. String sign-base of epidermis shows sharp demarcation like a string pulled along the base.

Answer 10

Compound Nevus

Compound melanocytic proliferation, nests in the dermis show good maturation. No atypia in the epidermal or dermal component.

Question 11

Answer 11

Syringocystadenoma Papilliferum

Cystic neoplasm opening onto surface. Epidermis shows hyperplasia and papillomatosis. Endophytic portion shows a papillary growth pattern with papillae composed of fibrovascular core surrounded by two layers of cells-inner tall columnar cells with eosinophilic cytoplasm and decapitate secretion and outer layer of small cuboidal cells. Numerous plasma cells in fibrovascular core.

Answer 12

Verruca Vulgaris

Papillomatous exophytic epidermal proliferation. Compact hyperkeratosis with vertical columns of round parakeratosis ending with hemorrhagic crust above peaks. Infolding of elongated rete ridges towards base. Granulation tissue like stroma.

Question 13

Answer 13

Cryptococcus

Suppurative and granulomatous inflammation with round yeasts (2-10 microns), free and within giant cells

Question 14

Answer 14

Erythema Annulare Centrifugum

Tight perivascular lymphocytic infiltrate (coat sleeving) with/without admixed eosinophils. Epidermis may show mild spongiotic changes.

Question 15

Answer 15

Prurigo Nodularis

Compact hyperkeratosis, focal parakeratosis and hypergranulosis. Irregular psoriasiform hyperplasia of epidermis, often with pseudoepitheliomatous hyperplasia. Occasional mild spongiosis. Collagen bundles in papillary dermis run perpendicular to the surface with admixed vessels and chronic inflammation.

Question 16

Answer 16

Lymphomatoid papulosis

Prominent dermal infiltrate of small lymphocytes, neutrophils, eosinophils and plasma cells with large atypical CD30+ T lymphocytes.

Question 17

Answer 17

Steven Johnson Syndrome

Necrotic/dyskeratotic cells at all levels of epidermis. Minimal to mild perivascular lymphocytic infiltrate with neutrophils and/or eosinophils.

Question 18

Answer 18

Macular Amyloidosis

Eosinophilic, acellular globules in dermal papillae, closely apposed to epidermis. Scattered melanophages in papillary dermis. Globules stain with crystal violet, Congo red and PAS.

Question 19

Answer 19

Telangiectasia Macularis Eruptiva Perstans (TMEP)

Basilar hyperpigmentation with mildly increased scattered mast cells in dermis, predominantly in a perivascular pattern. Usually spindled/fusiform morphology. Scattered dilated blood vessels. usually no eosinophils.

Question 20

Answer 20

Malignant Melanoma, Superficial Spreading Type

Atypical melanocytic proliferation with significant pagetoid spread within the epidermis. Contiguous proliferation of single cells and nests at DEJ. Severe cytological atypia of melanocytes.

Question 21

Answer 21

Linear IgA Vesiculobullous disease

Supepidermal split with papillary dermal edema. Linearly aligned neutrophils along DEJ. Superficial perivascular and interstitial neutrophilic infiltrate with admixed eosinophils and lymphocytes may be seen. DIF- Linear IgA at DEJ.

Question 22

Answer 22

Pilomatricoma

Multinodular tumor in dermis and/or subcutis composed of nests of basaloid nests resembling those of the hair matrix with abrupt transition to central shadow cells. Calcification and foreign body granulomatous response common. Numerous mitotic figures may be noted; never atypical.

Question 23

Answer 23

Lymphangioma

Dilated lymphatics at all levels of the dermis lined by a discontinuous flattened layer of endothelial cells and containing clear fluid.

Question 24

Answer 24

Hidradenoma Papilleferum Well circumscribed dermal lesion composed of densely packed glands with papillary projections into cystic lumina. glands lined by double layer of cells-inner tall columnar with eosinophilic cytoplasm and outer layer of myoepithelial cells. Decapitate secretions within lumen. No plasma cells.

Question 25

Answer 25

Coccidioidomycosis Granulomatous and suppurative dermatitis. Overlying pseudoepithelimatous hyperplasia with intraepidermal pustules. Uniform shaped sporangia (10-80 microns) with multiple endospores(1-4 microns) present both extracellularly and within giant cells.

Question 26

Answer 26

Angiosarcoma Poorly demarcated proliferation of anastomosing blood vessels (cracked collagen pattern) and solid areas. Vessels show atypical spindled or epithelioid endothelial cells with multilayering and papillary structures. Solid areas show sheets of spindle or epithelioid endothelial cells with significant atypical and mitotic figures. Luminal formation may be non-apparent and mitotic activity may be high, mimicking other high-grade sarcomas, carcinoma or melanoma c-MYC positive in Radiation associated lesions.

Question 27

Answer 27

Tumid Lupus Perivascular and periadnexal lymphocytic infiltrate.Increased dermal mucin.No interface changes at dermal-epidermal junction.

Question 28

Answer 28

Lichen Amyloidosis Hyperkeratosis, acanthosis, papillomatosis may be noted. Eosinophilic acellular globules in papillary dermis. Pigment outlining globules in papillary dermis. Globules stain with crystal violet, Congo red, PAS and keratin markers.

Question 29

Answer 29

Erythema Multiforme Basket-weave stratum corneum. Necrotic/dyskeratotic keratinocytes at all levels. Interface vacuolar dermatitis. Superficial perivascular lymphocytic infiltrate with/without eosinophils.

Question 30

Answer 30

Dermatofibroma Epidermis may show mild acanthosis with a table-top like proliferation. Moderately cellular proliferation of bland fibroblasts with admixed xanthoma-like foamy histiocytes. Collagen trapping is characteristic.

Question 31

Answer 31

Lichen Sclerosus Hyperkeratosis with follicular plugging. Epidermal atrophy. Homogenization of papillary dermis. Perivascular or band like lymphocytic infiltrate in early stages. Loss of elastic fibers in sclerotic zone, highlighted by VVG stain.

Question 32

Answer 32

Discoid Lupus Erythematosus Epidermal atrophy with overlying hyperkeratosis with follicular plugging. Vacuolar interface dermatitis and pigment incontinence. Thickening of basement membrane. Superficial and deep perivascular and periadnexal lymphocytic infiltrate. Increased dermal mucin (with Colloidal iron or Alcain blue stains).

Question 33

Answer 33

Dysplastic Nevus With Severe Atypia Composed of horizontally oriented nests, arranged haphazardly at the dermal-epidermal junction near the tips and sides of elongated rete ridges, with some nests bridging between adjacent rete along with confluent population of single melanocytes. Concentric papillary dermal fibrosis. Nuclear enlargement (more than twice the size of basal keratinocytes) with hyperchromasia and nucleoli throughout the lesion. Focal pagetoid scatter may be noted.Sparse to dense dermal inflammation, usually evenly distributed.

Question 34

Answer 34

Acute Generalized Exanthematous Pustulosis Subcorneal intraepidermal neutrophilic and eosinophilic pustules with admixed few acantholytic keratinocytes. background of spongiosis with neutrophilic exocytosis and scattered dyskeratotic cells. Papillary dermal edema. Perivascular mixed inflammatory infiltrate of lymphocytes, neutrophils and eosinophils. Vaculitis may be seen in dermis.

Question 35

Answer 35

Pseudoxanthoma Elasticum Short, wavy, fragmented, deeply basophilic calcified elastic fibers in dermis. Transepidermal elimination may be seen.

Question 36

Answer 36

Dermatofibrosarcoma Protuberens Short, wavy, fragmented, deeply basophilic calcified elastic fibers in dermis. Transepidermal elimination may be seen.

Question 37

Answer 37

Erythema nodosum Septal panniculitis with acute and chronic inflammation in septa. Lace like infiltration into lobules. Multinucleated giant cells and granulomatous response and septal thickening in chronic phase. Meischer granuloma- septal granulomas with central clear space.

Question 38

Answer 38

Trichotillomania Focally distorted hair anatomy. Increased catagen and telogen hairs. Empty anagen follicles with collapsed inner root sheaths. Minimal or no inflammation. Follicular plugging and pigment casts. Trichomalacia-distorted hair shaft with irregular pigmentation of shaft.

Question 39

Answer 39

Schwannoma Encapsulated lesion in dermis and/or subcutis. Cellular areas composed of closely packed spindle cells with tapered wavy nuclei and producing a palisading pattern(Antoni Type A areas). Intermixed less cellular areas showing scattered spindle cells in a loose myxoid background (Antoni type B areas). Blood vessels show hyalinized thick walls.

Question 40

Answer 40

Squamous Cell Carcinoma in situ Hyperkeratosis, parakeratosis, full tickness atypia of epidermal keratinocytes. No maturation.

Question 41

Answer 41

Blue Nevus Dendritic pigmented spindled melanocytes lesion in dermis with admixed melanophages and variable pigment. Dermal sclerosis common. Spindle cells strongly positive with HMB45.

Question 42

Answer 42

Lipoma Subcutaneous tumor composed of lobules of mature adipose tissue. Compressed pseudocapsule of fibrous tissue.

Question 43

Answer 43

Hailey Hailey Disease Extensive acantholyis usually at mid-epidermis resembling dilapidated brick wall. Follicle sparing, unlike pemphigus vulgaris. Focal dyskeratosis (eosinophilic band surrounding nucleus). Perivascular lymphocytes. Direct DIF-negative.

Question 44

Answer 44

Necrobiosis Lipoidica Diabeticorum Stratified layers of sclerosis and granulomatous infiltrate giving a layer-cake like appearance. Deep dermal and subcutaneous involvement common. Associated lymphoplasmacytic infiltrate with admixed giant cells. Focal areas of necrosis.

Question 45

Answer 45

Dermatophytosis Stratified layers of sclerosis and granulomatous infiltrate giving a layer-cake like appearance. Deep dermal and subcutaneous involvement common. Associated lymphoplasmacytic infiltrate with admixed giant cells. Focal areas of necrosis.

Question 46

Answer 46

Granuloma faciale Grenz zone. Nodular, dense mixed infiltrate with eosinophils, neutrophils, lymphocytes and plasma cells often in a perivascular pattern. Leukocytoclastic vasculitis may be present.

Question 47

Answer 47

Erythema Induratum Lobular panniculitis. Fat necrosis with associated suppurative and granulomatous inflammation. Caseating granulomas may be noted. Evidence of vasculitis in septa in form of inflammation around vessels with fibrinoid necrosis.

Question 48

Answer 48

Hemangioma Tightly grouped, well circumscribed proliferation of capillaries and venules in papillary dermis, often surrounded by an epidermal collarette. Some of the endothelial cell nuclei may be protuberant.

Question 49

Answer 49

Juvenile Xanthogranuloma Sheet like nodular aggregates of histiocytes, lymphocytes, eosinophils with admixed Touton-like giant cells in dermis and sometimes upper subcutis. Admixed foam cells.

Question 50

Answer 50

Polyarteritis Nodosa Necrotizing vasculitis with medium vessel vasculitis and fibrinoid necrosis of small to mid-sized arteries, usually in deep dermis or subcutaneous fat. Mixed inflammatory infiltrate with/without secondary panniculitis. Vessels at different stages of involvement is characteristic. Long standing lesions exhibit fibrosis around vessel walls with neovascularization of adventitia and loss of internal elastic membrane.

Question 51

Answer 51

Tuberous Xanthoma Predominantly interstitial infiltrate of foam cells in dermis arranged as small clusters or large nodules. Sparse admixed lymphocytes, neutrophils and eosinophils. Increased fibroblasts in older lesions.

Question 52

Answer 52

Granuloma Annulare Palisaded granulomas around areas of collagen necrobiosis and increased mucin. Perivascular lymphocytes with interstitial macrophages. Admixed eosinophils may be present.