ABSTRACT
Melanoma-associated leukoderma (MAL) is a depigmenting disorder occurring in 2%–16% of melanoma patients, either spontaneously or during/after immunotherapy. Although its pathogenesis remains elusive, it is considered an immune-driven manifestation illustrating the immunogenic nature of melanoma, and may impact prognosis. Increasing evidence suggests that MAL results from a cytotoxic T-cell cross-reaction directed against antigenic determinants shared by normal and malignant melanocytes. Such spontaneous or therapy-induced antitumoral immunity is clinically evident as depigmentation. At least three types of leukoderma have been associated with melanoma: (1) hypomelanosis within melanocytic lesions (primary, recurrent, or metastatic) due to regression, (2) amelanosis surrounding tumors (halo phenomenon), and (3) vitiligo-like depigmentation in sites remote from the primary tumor. Since the development of MAL seems to carry a favorable prognostic relevance on the clinical course of melanoma, it may provide prognostic information or indicate response to treatment of a known melanoma patient. Moreover, as depigmentation can precede melanoma detection, awareness of this phenomenon would prompt a thorough investigation aimed at suspicious melanocytic lesions. From a therapeutic perspective, insight into the immunology behind MAL could further advance the development of approaches to combat melanoma by identifying potential targets for immunotherapy.
