Case Number : Case 2624 - 28 July 2020 Posted By: Uma Sundram

multifocal basaloid proliferation with a cracking artifact seen in image 1 ? Superficial spreading BCC

I think this lesion has a specific follicular stroma, therefore it may be more accurate to call it trichoblastoma. Due to multifocality, It resembles trichoblastoma arising in nevus sebaceous, although there are no signs of nevus sebaceous in this biopsy.

Nevus Sebaceous with follicular induction. 

I was struck by the very high-lying sebaceous glands which I presume indicates a naevus sebaceous, although of course the trunk is an uncommon site.  I think the basaloid downgrowths are multifocal superficial BCC.  There appears to be a retraction artefact visible on the left of images 1 and 2.

My first thought is superficial BCC (there is a retraction artefact in images 1,2)

Superficial BCC. We thought the BCC was associated with some sebaceous differentiation, bit did not think this was nevus sebaceus, due to the morphology and the site. We did not favor sebaceous carcinoma, although that thought crossed our mind.

Ok. I was wrong with nevus sebaceous. Interesting case. Thanks Uma!

I don't think you were wrong! Superficial BCC-like trichoblastoma. Probable naevus sebaceous associated (would need a history of a pre-existing lesion). CK20 & CD10 can be useful adjuncts.