In this issue of The Melanoma Letter, my co-editor, Dr. Marghoob, and my very close colleague, Dr. Jaimes, provide an excellent review of our current state of knowledge of the relatively rare and clinically challenging entity ‘desmoplastic’ melanoma. The phenomenon of desmoplasia can be superimposed on all four commonlyconsidered ‘histogenic subtypes’ of melanoma (superficial spreading, lentigo maligna, acral/mucosal, and nodular), but as the authors note, is most frequently associated with lentigo maligna melanoma(LMM) and to a lesser extent with superficial spreading melanoma. The association of desmoplasia with LMM, chronic sun exposure, and advanced age is quite important, because it suggests that the incidence of desmoplastic melanoma can be anticipated to increase significantly with the aging of the population.
These melanomas are challenging to clinician and pathologist alike because they typically lack a melanoma-like appearance either clinically or histologically. Accordingly, a high index of suspicion is critical to their early detection. Even once correctly diagnosed, desmoplastic melanoma presents unique challenges in clinical management, given its propensity to involve nerves and recur locally. The authors explore these issues in detail along with the relatively recent observation that desmoplastic melanoma may differ in its biologic behavior based on the histologic extent and homogeneity of the desmoplasia. This distinction between ‘pure’ and ‘mixed’ desmoplastic melanoma is only recently becoming more widely appreciated, more consistently reported by pathologists, and more seriously considered in the management of these patients.
Allan C. Halpern, MD