BAP1-Inactivated Melanoma Arising From BAP1-Inactivated Melanocytic Tumor in a Patient With BAP1Germline Mutation: A Case Report and Review of the Literature

BAP1-inactivated melanocytic tumors represent a subset of epithelioid melanocytic neoplasms resulting from biallelic inactivation of the BAP1gene and by a driver mutation that activate the MAP kinase pathway, most commonly BRAFV600E. They occur sporadically or, less common, in the setting of BAP1tumor predisposition syndrome caused by a BAP1germline mutation that predisposes to several malignancies including cutaneous and uveal melanoma. To date, only few cases of BAP1-inactivated melanomas have been reported. We present a case of a 35-year-old woman presented with a melanocytic lesion microscopically composed of 3 distinct melanocytic populations, suggesting a stepwise progression model to melanoma from a conventional nevus through a melanocytoma stage. This progression was also supported from a molecular viewpoint given BRAFV600E, BAP1, and TERT-phot spot mutations detected by targeted mutational analysis. Four atypical melanocytic lesions were removed from the patient's back, and the same A BAP1c.856A>T, p.(Lys286Ter) mutation was detected on either tumoral or normal tissue samples. To the best of our knowledge, this is the first case of BAP1-inactivated melanoma with a documented TERT-phot spot mutation manifesting as the first presentation of BAP1tumor predisposition syndrome.