Complete regression of primary melanoma associated with nevi involution under BRAF inhibitors: A case report and review of the literature

Melanoma is one of the most immunogenic tumors among human neoplasms, with numerous clinical observations of partial or completely regressed tumors. It is an aggressive tumor, with the greatest reported number of somatic mutations, BRAF mutation being the most common one. BRAF mutation is also present in a higher percentage in benign nevi. Complete regression of primary tumor and involution of nevi are, however, rare phenomenon in melanoma that can appear in relation with UV exposure, surgical trauma, target therapy in melanoma, pregnancy or host immune response to an evolving melanoma tumor. We present the case of a 58-year-old man with a completely regressed metastatic melanoma who developed a second melanoma with concomitant involution of papillomatous nevi under BRAF inhibitors treatment. In reviewed literature we have found 53 cases of completely regressed primary melanomas, neither of them reporting nevi involution. Complete regression of primary tumor can occur as an immune response to tumor progression. Nevi can involute under BRAF inhibitor therapy, but development of new malignant lesions under BRAF inhibitors is linked to BRAF wild-type. Documentation of primary tumor and dynamic changes in nevi highlight the need of a good clinical skin examination and increase the utility of baseline and sequential dermoscopy in melanoma.