Case Number : Case 1422- 4 December Posted By: Guest

Agree, invasive follicular SCC

Nice, totally agree. I did not know about this entity and I was hesitating on making a simple diagnosis of well differentiated squamous carcinoma without seeing continuity of the tumor with the epidermis. Thanks for illustrating me. I leave an article that I found about it:

Follicular cutaneous squamous cell carcinoma: an under recognized neoplasm arising from hair appendage structures. Magro CM, et al. 

Yes, folicular SCC.

KA is a good thought too, certainly with the distinctive pattern of keratinisation maintained throughout the tumour and the elastotic material. There is quite a bit of cytological atypia and I think this is one of the (many)  controversial aspects of KA . Some will consider this indicative of SCC, whilst others would easily accept this degree of atypia in a KA. Clinical history is ofcourse important (?rapidly growing lesion)

I'm sure Richard will educate us on this!

Just seen the immunos...B catenin positive ??? 

I had wondered about pilomatrical differentiation when I looked at the images  and looking at them again, are there ghost cells in image 4 and red trichohyalin granules in image 5?

So, is this follicular SCC with pilomatrical differentiation???...probably completely on the wrong track!!

Beta catenin expression is quite particular as is seen mainly on tumors with matrical differentiation

Well it has taken a little while but seems I have caught you all today.  This is of course a "follicular" carcinoma but sadly not the one I have been banging on about - i.e. Infundibular-tricholemmal although the top bit would be typical for that diagnosis.  Arti has correctly rescued it with the IHC but the trichohyaline (bright orange) granules and ghosted keratinocytes throughout were a good clue to a pilomatrical neoplasm.  So yes given that there is significant pleomophism and despite the rather circumscribed profile I opted for a pilomatrical carcinoma.  I think this will have a very low risk for metastasis given the circumscript borders.  I guess you could argue for a malignant panfolliculoma but I am not certain the limited superficial infundibular/isthmic component is not just reactive in this case.  I put the EMA in to indicate it was not a BCC with matrical differentiation (also diffuse nuclear/cytoplasm Beta-catenin is typical for metrical tumorus). Great Royal College Update meeting today in London.  Warm regards from the train back to Warwick.