Case Number : Case 2032 - 19th March Posted By: Uma Sundram

BCC with focal sebaceous differentiation or sebaceoma. Point in favour of BCC is the clefts between stroma and tumour islands. CK 7, EMA and Ber-EP 4 stains needed for DD

Agree with sebaceous differentiation, but my first thought is of a carcinoma(high grade). 

Porocarcinoma with foci of en masse necrosis, best seen at picture 1, left top.

Dr Chaudhry: I considered porocarcinoma - but difficult case!

What do you guys think about the 5th figure? I think there are some lumen formation or ductal differentiation. In addition , looks like there are some vessels / fibrovascular cores in the largest nest. In most carcinomas, we rarely see fibrovascular cores in the nests of maignant cells. Everytime I see fibrovascular cores in a nests of tumor like that, i start thinking of solid papillay carcinoma. In the skin, we can see that in endocrine mucin producing swear gland carcinoma. 

Wow, what great comments!

EMA and BerEp4 were negative. CK7 was negative. Both p40 and p63 were positive. We went with poorly differentiated invasive SCC. The patient had significant morbidity so the clinician was wondering about the use of a PD-L1 blocker in this patient with fairly significant advanced disease of a lesion that was difficult to resect. Some benefit has been shown with SCC of the head and neck. However, this patient did not have microsatellite instability issues (MSI) or loss of repair proteins such as that which can be seen in Muir Torre, and MSI-H is a positive criteria for the use of the drug.

Nice case!