Derm Path Flashcards
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)
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!!!
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)
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)
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)
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
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
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
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
Merkel cell?
Cutaneous NE carcinoma
CK20+ dot like, P63+ (bad prognosis), Synapto and Chromo +
Does not palisade like BCC
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
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)
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
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
Eccrine Poroma?
Basaloid proliferation; epidermal connection; has DUCTS
Looks like SebK but “funny”
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-
