Case Number : Case 1862 - 18 July - Dr Uma Sundram Posted By: Guest

Angiofibroma aka fibrous papule of face

nuclear features, mast cells and myxoid stromal change make me think of a neural lesion: neurofibroma, solitary circumscribed neuroma and even perineurioma. would have done S100, EMA, GFAP.some degenerate changes reminiscent of schwannoma but no capsule.

Dermatomyofibroma

Kaposi sarcoma

I think this is one of those cases where the immunos clear easily the pathway. Would perform S-100, Desmin, CD34 and CD31. Morphologically I see a prominence of vessels that strikes me, some even with a staghorn morphology, there are also some areas that look myoid. For me this is Myopericytoma/Myofibroma vs Neurofibroma to confirm with immunos

Agree with the comments made by Raul. Needs IHC. More for a myopericytoma.

The silhouette is one of a plaque in medium deep dermis. The spindle cells lie side by side in bands parallels to epidermis and show abundant esosinophilic cytoplasm. There is often a contiguity relationship with the angiectatic vessels, angioleiomyoma-like. 

For all these reasons my favorite spot is Dermatomyofibroma.

Odd site, I know. And actina and desmin are many times negative in dermatomyofibroma. 

I favor a nerve sheath tumor, particularly diffuse neurofibroma. The short fusiform cells display wavy hyperchromatic nuclei and permeative pattern of growth. There are sparse mast cells interspersed among them. In the last image, some elongated structures are reminiscent of Wagner-Meissner corpuscles to my eyes.

My impression is also neural; neurofibroma may be with some ancient changes. S100 can easily confirm. 

Great DDX and I always love these discussions! The analysis of a series of photomicrographs with a DDX based on morphology is a lost art (at least, unfortunately, in the US). This is a young man with a long standing nevus on the scalpe where the clinician neglected to give us the superficial aspects of the lesion; the nested appearance of the superficial dermal component would have clinched the diagnosis. S100 and MART1 (Melan A) were both positive in lesional cells. Also interesting to note various features often associated with 'soft tissue tumors' such as staghorn vessels.

So, final diagnosis is long staving nevus?

'standing