Case Number : Case 2001 - 06 Feb 2018 Posted By: Iskander H. Chaudhry

A tumour of poroid cells showing exophytic growth pattern, ductal structures, necrosis and mitoses.At places seen to be infiltrating the dermis. A poroma turning malignant ?

Yes porocarcinoma came to my mind too, CEA could highlight the ducts

Agree with porocarcinoma

I don't see any ductal differentiation. Why not a sebaceous carcinoma, LOW GRADE?

These cells look really big and vesicular. I'm going to be a wimp and say 'adnexal tumor, NOS'. I like porocarcinoma, though. Another thought is a really poorly differentiated SCC with ?viropathic changes? I see some pigment too but really think it's epithelial.

BCC sine palisading and retraction artifact

BerEp4 is often positive in Sebaceous Carcinoma. 

IHC would be okay for BCC. I'd probably go for either an odd BCC or trichoblastoma. Morphologically sebaceoma was a consideration but BerEP4 is almost always negative. An entirely circumscript sebaceous carcinoma (in situ) may be a possibility. I see some mitotic activity but not much in the way of cellular pleomorphism. I'd like to add adipophilin, CD10, CK20, Ki67, p53. I was least in favour or a poroid/ductal tumour. Funny as I have quite a similar case on my desk right now!  I don't think there is any metastatic potential with the circumscription we see here it's ultimately a little academic but rather a fun puzzle!

A sebaceous tumour is my prime suspicion! The cells are germinative rather than poroid so not in favour of porocarcinoma. An adipophilin is a must as sebaceous differentiation may be very focal/subtle. If its is sebaceous, would best fit with an insitu sebaceous carcinoma. 

Dr Chaudhry:

Classed as adnexal carcinoma favouring sebaecous - the lesion is not entirely in situ. Adipophilin requested and update to follow!

Is there some pigment?

Any melanocytes for melanocytic matricoma?