Desmoplastic melanoma is an often missed lesion and can be the bane of the dermatopathologist's existence. It will resemble a scar, both clinically and histopathologically. When it recurs, it will also resemble a scar and may recur several times before the correct diagnosis is made. Desmoplastic melanoma often presents with a higher Breslow level than other subtypes, but patients do remarkably well given the same pathologic stage and tumor depth, suggesting there is a different biology in these tumors. This case shows a pure desmoplastic histology, and recent studies suggest these rarely metastasize as opposed to their brethren with mixed desmoplastic and conventional histology. Immunohistochemical analysis can be helpful as the tumor will almost uniformly stain with S-100. Other melanocytic markers are typically negative.
The low power view shows fibrosis. There are scattered lymphoid aggregates, extending deep. The increased cellularity is not evident at this power. An epidermal component is also not seen.