Case Number : CT0120 Adam_Bates

Intraepidermal proliferation of atypical epithelioid large cells with ample cytoplasm and prominent nuclei, some show intracytoplasmic lumina..Few cells are showing pagetoid spread, Will go for Extramammary Paget's disease..
 

I would go for the differential: melanoma, SCC, sebaceous carcinoma, Paget´s, and ask for inmunohistochemistry EMA, CAM 5.2, melan A
 

I posted a comment on the connective tissue naevus case (not overly helpful I must admit - but bascially it fitted with the clinical diagnosis). ON this case I favour paget's/EMP. Our panel is, Alcian blue/DPAS, BerEP4 (all Pagets/EMP); Cam5.2 (all Paget's/EMP but neg in pagetoid Bowen's and melanoma); S100 (for melanoma with other markes neg.) For EMP would do CK7/CK20 (secondary urothelial is CK20 +ve as is rectal adenocarcinoma. Primary EMP of vulva and anus can be CK7+ and CK20+ especially apocrine). Extrammary Pagets: CK7-/CK20+ phenotype would suggest rectal tumour in perianal/perineal disease. You can also get intra-epidermal Merkel cell carcinomas and need to consider in the differential of pagetoid lesions (but not this case).
 

Extramammary Paget's disease.
 

I bet Paget disease.
 

The diagnosis is Extra-mammary Paget's disease. In some areas you can see the basal keratinocytes below the Paget's cells. Well done to all those who posted and thank you Richard for posting your comments on the connective tissue naevus case. Next case tomorrow.
 

paget extramamaria