Derm Path Flashcards by Ben Saylor

Keratoacanthoma, mimicing?

Pagetoid SCC mimickers?

Fibroepithelial pinkus

Well diff glassy proliferation of atypical keratinocytes in crateroform pattern; microabscesses associated with

Mimics: Chromoblastomicosis (copper pennies)

SCC: Pagets and Melanoma (look for bridges)

FP: BCC growing down adnexal structure; mimics (syringofibroadenoma and poroma)

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Trichilemma?

Finding at edges?

Small solitary asymptomatic papular lesion on face

Shart circumscribed borders, lobules into upper germis with continuitiy with epidermis

Peripheral layer of clear/glycogenated palisading cells with thicken glassy basement membrane!!!

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Tumor of follicular infundibulum?

Trichofolliculoma?

Subepidermal tumor composed of reticulated cords and nests of pale/pink staining glycogen containing cells (not blue which seperates from superficial basal)

Trichofolliculoma: One or several dialted hair follicals and radiates small hair follicles (little babies)

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Trichoepithelioma (mimics BCC)

Islands of basaloid cells with some peripheral palisading

Fibroblastic stroma; Epithelial structures resembling hair papillae and aggregation of fibroblasts around these (papillary mesenchymal bodies)

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Desmoplastic Trichoepithelioma?

Face; well circumscribed in upper and mid dermis; central depression

Cords and small nests of basaloid cells with scant cytoplasm

Many keratinous (horn cysts)

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How to DDx Demsmoplastic trichoepithelioma vs BCC?

Trichoepitheleoioma associations?

DTE: Lacks retraction and apoptosis (more common BCC)

DTE: SPindle cells around islands (CD34+) vs CD34- cells in BCC

BCC: Diffuse BCL2 vs DTE in basal layer only

Multiple family: CYLD gene on 16q12-13; Brooke-Spiegler syndrome

Cowden’s Multiple trichelemmomas (PTEN 10q23.31)–PTEN hammartomous tumor

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Pilomatricoma?

Differentations to hair matrix and hair cortex of inner sheath

Calcifying epithelelioma of Malherbe

Sharp demarcation in lower dermis/subq

Basophilic cells and SHADOW CELLS

Often calcified

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Fibrofolliculoma/trichodiscoma?

Fibrofolliculoma: Cords/strands of epithelial cells, 2-4 cells thick radiating from follicular structrure with a surrounding well circumscribed proliferation of loose connective tissue with fine fibers

Looks a bit like neurofibroma/desmoplastic melanoma but key is “radiating strands” in epidermis

Trichodiscoma: Well demarcaded but non encapsulated; come collarette of follicularsebaceous cells but no surface bridging

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Birt-Hogg-Dube gene, transmission pattern?

Associated wtih?

AD, FLCN (BHD) Ch 17p12 folliculin protein

Oncocytic neoplasms and chromophobe RCC, Cutaeneous fibrofolliculomas, Lung susts and spontaneous pneumothorax

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Merkel cell?

Cutaneous NE carcinoma
CK20+ dot like, P63+ (bad prognosis), Synapto and Chromo +

Does not palisade like BCC

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Molluscum casued by?

Verruca vs Condyloma Accuminata

Pox virus with Henderson Patterson Bodies

Condyloma: more mamillated with more vessels; also more likely to be in genetals

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Cylindroma?

Spiradenoma?

Dermal tumor of “irregular hsapped” island/chords in JIGSAW PUZZLE with HYALINE MEMBRANE AROUND

Spiradenoma: Basophilic nodules in dermic; trabecular arrangement of small dark cells and larger paler cells with prominent stroma (similar to Cylindroma and can sign out together)

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Syringoma?

Clinical: Multiple small papules on lower eyelids and cheeks (critical to differentiate from microcystic adnexal carcinoma)

Dermal tumor of small ducts; 2 layers of epithelium, comma tails, strans of basaloid epithelium, dense REDISH stroma

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Microcystic adnexal carcinoma?

Dilated ducts and keratin filled cysts in upper dermis, PNI is present if deep biopsy

These lesions extend deep to diff from synringoma

Clinical: Plaque (one) on lips normally upper

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Eccrine Poroma?

Basaloid proliferation; epidermal connection; has DUCTS

Looks like SebK but “funny”

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Nodular hidradenoma?

Cutaneous mixed tumor (Chrondroid syringoma)

Cells look like poroma in large nodules with some degeneration; Has ducts as well (CK7+, EMA+, CEA+)

MIxed tumor: looks like pleomorphic adenoma of epithelial, chondroid and mesenchymal elements

Hidradenoma papilliferum?

Vulvar/Perinal regions (likes to HIDE In dermis)
Solitary nodule <1 cm in mid age women

Partially cystic with papillary and glandular areas (arborizing trabecular pattern); Not connected to surface; No inflammatory pattern

Syringocystadenoma Papilliferum?

Scalp and forehead (vs hidradenoma papilliferum)

Raised watry plaque or flat

Organoid nevus in 1/3rd

Duct like structures invaginationg from surface (vs deeper in HP); lined by squamous double layered epithelium of cuboidal/collumnar

PLASMA CELLS and Inflammation

Nevus sebaceous/Organoid nevus, Nevus sebaceous of Jadassohn?

Present at birth, head and neck/scalp

Tan brown, alopecia, rought, verrucoid in puberty,

As these age things arise in them

H and E: Increase Sebaceous glands in dermis, abnromal hair follicles (vellus instead of terminal), and apocrine glands

Sebaceous adenoma?

H and E?

Multiple might indicate?

Head and neck older patients, Tan-yellow nodule/nodules <1cm

H and E: Multilobular with several contiguous lobules that connected to epidermis

Central mature sebocytes dominate

NO CYTOLOGIC ATYPIA or ATYPICAL MITES

Multiple: Muir Torre (Lynch AD MLH1, MSH2, MSH6 issues); multiple carcinomas in body; Cystic sebaceous adenoma

Sebaceoma vs sebaceous adenoma?

Sebaceous carcinoma?

Sebaceoma >50% basaloid cells; dermal with oly focal epidermal attachments

More mites

Carcinoma: Low power infiltration is best predictor; AR+; can be squamatoid

T/F Extramammary Paget’s has underlying tumor?

F; CK7+, EMA+ (to differentiate from melanoma or pagetoid SCC)

Dermatofibroma?

H and E?
Collagen?

IHC?

Brown lesion

Poorly demarcated tumor in dermis; Admixture of fibroblast like cells and histiocytes

Collagen trapping at periphery

Epidermal changes including acanthosis, basal hyperpigmentation a,d follicular induction

CD10+, FXIIIa+, CD34- (+ in DFSP)

DFSP?

IHC?

Slow growing: infiltrates in to subq

Fasicles of uniform, spindle cells with plump nuclei and intermingled collagen; dives into fat

p75+, CD34+ (lost with fibrosarcomatous change); FXIIIa-

Atypical fibroxhantoma, location? H and E? IHC?

Head and neck Non encapsulated highly cellualr **atypical cells; plump, spindle cell in poorly arranged fasicles** DX of exclusion; (2 keratins, 2 melanocytic) CD10+

Neurofibroma? H and E? IHC?

**Grows by expanding nerve** (vs schwannoma coming off nerve) Delicate oval/spindle nuclesus, **scant indefinitive cytoplasm, MAST cells** **S100+**, Factor XIII+, CD34+; vs desmoplastic melanoma FXIII-, CD34-

Palisaded and Encapsulated neuroma, location? H and E? IHC?

Face old person **Dermal nodule with multinodualr plexiform growth pattern with fasicles with clefts** EMA+ around capsule

Kaposi? Virus

Dermal spindle cell proliferation of jagged vascular channels with promontory sign (vessel inside of vessel) HHV-8+

Desmoplastic melanoma?

Sneaky melanoma; **low power shows lymphoid nodules around it**

Blue nevus? Clark's/dysplastic nevus?

Pigmented spindled melanocytic cells in dermis (vs desmoplastic melanoma which tends to not be pigmented--for boards) Clark: Nuclear enlargement/ pleomorphism, fusions of melanocytes, **lamellar fibroplasia, shoulder (epidermal component beyond dermal component)**

Spitz nevus? H and E? What is at DEJ?

Papule or nodule on face, trunk, or extremities of **children or young adultsb** Epithelioid or spindle cells, **Symmetrical, epidermal hyperplasia, Pagetoid melanocytes centrally; tends to end in a nest** **Eosinophilic globules (Kamino bodies) at DEJ** **MATURATION OF DERMAL COMPONENT**

Melanoma clues?

Doesn't mature deep and has lots of single cells at the edge in many cases

3 Stages of Mycoides fungoides? CD's?

Patch, plaque, and tumor Patch: Erythematous patches irregular in shape, **Random distribution/sun protected sites** Mild superficial perivascular lymphocytic infilatrate and epidermis without spongiosis (cells in dermis are NOT MF); **Birds on a wire** **Loss of CD7 and CD5, CD3+, CD4+; T-cell gene rearrangement**

Lymphoid papulosis? H and E? IHC?

**Crops of papules, nodules at different stages SPONTANEOUS REGRESSION after a few weeks**, some scars H and E: Wedge shapped mixed cellular dermal infiltrate with large atypical cells (**CD30+**) Other types that mimic MF and ALCL BUT need clincal hx

Primary Anaplastic Large Cells? H and E? IHC?

Solitary or localized papules, nodules, tumor **Confluent sheets of large anaplastic cells with round, oval, indented nuclei** **CD30+, ALK- (**ALK+ think cutaneous spread of primary systematic ALCL)

Desmoplastic melanoma histology? IHC?

Spindle cells in dermis with atypia **Mart1-, HMB-45-, Diffusely S-100 +, SOX10+, CD34-, FXIIIa-**