Case Number : Case 2516 - 27 February 2020 Posted By: Saleem Taibjee

Neurofibroma.

My question is: a perineurioma or a mixed perineurioma and neurofibroma? 

There are two types of spindle cells: a) more slender with tapered nuclei b) more plump...so I think this is a hybrid neural tumor.

I have seen a very similar case, but the patient was known to have neurofibromatosis NF1. Usual neurofibromas are not encapsulated. So I've called it plexiform neurofibroma, despite only one nodule was present. 

Let me correct my mistake: not a perineurioma and neurofibroma, but perineurioma and Schwannoma. I see an intimate admixture of Schwann cells and perineurial cells, in a well circumscribed and unencapsulated proliferation, with a distinctive whirling pattern. So favor a hybrid Schwannoma and perineurioma.

Agree with Vincenzo. Hybrid perineurioma and schwannoma.

S100, EMA and CD34 will be nice to c. I favor hybrid perineurioma/shwannoma lesion

The immunos follow below. EMA and CD34 positive, but S100 negative. Hence I favoured a 'pure' perineurioma. We don't have Claudin in our lab, but that would be another potentially useful stain. BW Saleem