Skin - tumours Flashcards
HG spindled lesions
AFX (no necrosis, LVI or deep invasion)
spindled SCC
melanoma
leiomyosarcoma
low grade spindled lesions
dermatofibroma
DFSP
nerve sheath (neurofibroma, schwannoma, perineurioma)
cellular blue nevus
Kaposi sarcoma
desmoplastic melanoma
DF vs DFSP
DF: epidermal hyperplasia, collagen trapping, birefringent collagen, F13a+, CD34-
DFSP: invades subcutis, F13a-, CD34+
solitary lesion with lichenoid inflammation
lichen planus-like keratosis
irritated seborrhoeic keratosis
solitary lesion with acantholysis
acantholytic acanthoma
warty dyskeratoma
acantholytic actinic keratosis
acantholytic SCC
clear cell epidermal neoplasms
clear cell acanthoma
tricholemmoma
SCC in-situ
infiltrative skin lesions
infiltrative BCC: clefts, myxoid stroma, pallisading
desmoplastic trichoepithelioma: single lesion, cheek of young women, small keratin cysts
syringoma: multiple, around eyes older women, tadpole shaped ducts
MAC: superficial microkeratocysts, ducts and strands, deep infiltration, PNI
junctional lesions
poroma
tricholemmoma (Cowden’s if multiple)
BCC
naevus
myxoid skin lesions
digital mucous cyst
digital fibromyxoma
dermal nerve sheath myxoma (s100+)
superficial angiomyxoma (Carney complex if multiple, epithelial component common eg cyst)
myxoid DF
myxoid DFSP (CD34+, PDGFRB mut)
myxoid NF (s100+)
LG fibromyxoid sarcoma (MUC4+, FUS rearranged)
myxofibrosarcoma
histiocytoid infiltrate
LCH: CD1a, s100+
JXG: Touton giant cells
lymphoma: atypical lymphoid cells, LCA/T cell markers
mastocytoma: CD117, mast cell tryptase
Spitz nevus and pigmented spindle cell nevus (Reed) vs melanoma
Spitz/Reed: symmetrical, Kamino bodies, no Pagetoid disease, HMB45 decrease with depth
Spitz only: crescent clefts, p16+, FISH panel
special site nevus - features and melanoma differential
acral nevus: lentiginous component, Pagetoid spread
genital nevus: rete nests, discohesion
both sites (vs melanoma): symmetry, dermal maturation, no deep mitoses
Painful skin lesions
ANGEL
angiolipoma (peripheral capillaries with microthrombi)
traumatic neuroma
glomus tumour (SMA+, also glomangioma/glomangiomyoma)
eccrine spiradenoma (cannonballs in deep dermis, 2 cell types)
vascular leiomyoma