Case Number : Case 2842- 28 May 2021 Posted By: Dr. Richard Carr

Sir, No comments, you are ultimate, i will try and learn

P53 is increased, P16 nuclear and cytoplasmic positive- invasive follicular squamous cell carcinoma

p53 > but p16 isn’t null as expected in fSCC, so it’s difficult , for me, making a diagnosis based on these markers. Not sure, but...how about a proliferating pilar tumor?

I'll wait for a few more comments

Those brave soles who did comment did not note the sebaceous differentiation or relative lack of significant cellular plemorphism or the rather organoid architecture. The patient has Muir Torre syndrome (MTS) and has had many sebaceous adenomas. I concluded this was sebaceous adenoma with striking squamous differentiation (probably from the sebaceous duct) i.e. a seboacanthoma. I could not find much on google but according to wikipedia! these types of lesions may be specific to MTS. p16 is up-regulated mosaic (wild type) and p53 shows up-regulated wild type (nice gradation in staining from stronger peripheral to weak and negative centrally - as discussed last week). The lesion had been seen by two other pathologists who had favoured a well differentiated squamous cell carcinoma

Yes. Now I’m seeing the nice sebaceous diff. Thanks, Richard. I was off the track, with my guess!

yes we are able to appreciate the sebaceous component