A challenging case of Pure Desmoplastic Melanoma

Background: Desmoplastic melanoma is a rare tumor that develops preferentially on chronically sun-damaged skin of elderly patients. Its clinical appearance may be deceiving, often characterized by a slow-growing amelanotic and indurated plaque or nodule, leading to a delayed diagnosis in most cases. Histologically, it can present as two forms: 1) Pure (>90% desmoplasia), clinically more insidious and with a more sarcomatous behavior; and 2) Mixed. Overall, the survival of desmoplastic melanoma may be comparable to SSM type melanoma when matched for tumor thickness, probably due to its high tumor mutational burden.