Case Number : Case 1878 - 09 August - Dr Uma Sundram Posted By: Guest

Pleomorphic fibroma

Angiofibroma. 

I'm struggling. I find this sort of spindle cell lesion tricky and invariably end up doing a few immunos. My differential including: perineurioma, neurofibroma, hypopigmented blue n., desmoplastic naevus.

Looks neural to me too

Looks neural to me too, perinurioma?

Agree with the differentials proposed by Richard. Favour a neural tumour ? Perineurioma

I was thinking of mutinucleated cell angiohistiocytoma, but I'm afraid I'm wrong, if no other thought of this lesion...

I looked for alternative diagnosis ( as perineurioma or some  smooth muscle proliferation ), but this lesion has a typical plaque-like silhouette, and typical angulated multinucleate cells, so favour MCA.

Some of the cells looks like mast cells.

Just to widen the differentials , the following are added with different priorities;Giant cell collagenoma (GCC) ,multinucleate cell angiohistiocytoma , circumscribed storiform collagenoma, pleomorphic fibroma/lipoma, regressive forms of dermatofibroma, solitary myofibroma,  giant cell fibroblastoma , neurofibroma, giant cell angiofibroma .

pleomorphic fibroma if other d/d (as above) excluded by immunos.

My apologies for the late post. We did call this an unusual neurofibroma. Sox10 and s100 were positive but other melanocytic markers were negative.