Extramammary Paget Disease

Epidemiology:

Common sites:

• vulva (labia majora)
• perianal

Gross features:

• red
• crusted
• sharply demarcated, map-like area

Histologic features:

• large atypical tumour cells, singly or in small clusters, within the epidermis and its appendages
• clear separation (“halo”) from the surrounding epithelial cells
• rim of normal keratinocytes between the tumour cells and the dermis
• finely granular cytoplasm
• PAS, alcian blue, or mucicarmine positive

Immunophenotype:

Marker:	Sensitivity:	Specificity:
CK7
CEA
EMA
CAM 5.2
GCDFP	Most
CK20 (neg)	Usually
ER (neg)
PR (neg)

Molecular features:

Other features:

• often recur