Case Number : Case 2699 - 10 November 2020 Posted By: Uma Sundram

Follicle-based growth pattern, with some worrisome feature (  low grade atypia, pseudo-infiltration and trichilemmal differentiation with inverted follicular keratosis )...Difficult!

?Low grade trichilemmal carcinoma.  ?An odd desmoplastic trichilemmoma. ?Low grade fSCC ( as I learned thanks to Richard Carr )-

Agree with follicular differentiation. Not sure what to call it. The overall architectural features somewhat appear like a Pilar sheath acanthoma to me. But there is definitely atypia which doesn't go with it. 

Hmm... Am surprised there aren't more comments. We too were somewhat stumped for an answer. We finally landed on follicular tumor with trichilemmal differentiation. We did not call it an outright malignancy. It was excised and we did not recommend further therapy.

Thanks a lot Dr, just stumped, did not know how to label it

On 12/11/2020 at 17:09, Uma Sundram said:

Hmm... Am surprised there aren't more comments. We too were somewhat stumped for an answer. We finally landed on follicular tumor with trichilemmal differentiation. We did not call it an outright malignancy. It was excised and we did not recommend further therapy.

Cant this be BCC.. peripheral palisading is obvious in some nests.??