Case Number : Case 2035 - 22 March 2018 Posted By: Dr. Richard Carr

Desmoplastic melanoma ?

When I see a dermatofibroma like melanocytic lesion my first spot is desmoplastic Nevus(spitzoid).  There isn’t any convincing cellular atypia , instead the cells look like spitzoid cells. Forearm are frequently involved by DSN. MelanA support my spot.  But I find this a difficult case. 

Desmoplastic Melanoma.

Although been rare on desmoplastic melanoma cases, positivity for Malan A can be seen in some cases. The presence of inflammation best seen on the right sided pictures favors desmoplastic melanoma. It is a difficult case, but I believe this tumor has a malignant behavior.

Desmoplastic Spitz nevus? 

The cells in desmoplastic melanoma are usually spindle in shape with hyperchromatic nuclei and almost no cytoplasm, just look like fibroblasts in my experience. The melanocytic cells in this lesion appear epithelioid with clear cut eosinophilic cytoplasm. The stroma appears rather sclerotic than desmoplastic in my eyes. The vascular pattern is also kind of unusual for a desmoplastic melanoma. I therefore woud favor a Spitz nevus.

For the reasons outlined by Vincenzo & Anh, I called this a angiomatoid & desmoplastic Spitz naevus.