Desmoplastic melanoma: recent advances and persisting challenges.

Desmoplastic melanoma is an uncommon variant of melanoma which presents significant challenges to the clinician and histopathologist. In particular, many cases show a bland 'fibroblastic' appearance, mimicking scar and a range of other benign proliferations. This diagnosis can be particularly problematic in small biopsy specimens, a difficulty exacerbated by an immunoprofile which is typically negative for a number of conventional melanocytic markers. The clinical and histological features of desmoplastic melanoma are reviewed, as are the differential diagnoses and some newer techniques which may contribute to assessment of these lesions. In recent years it has become clear that subclassification of desmoplastic melanoma into pure and mixed variants has clinical significance and it is suggested that this classification be employed in routine practice.