Carriers of heterozygous germline pathogenic variants (PVs) of BAP1 are affected by a hereditary condition called BAP1 tumor predisposition syndrome (BAP1-TPDS), characterized by predisposition to a wide range of tumors, whose core spectrum includes mesothelioma, cutaneous and uveal melanoma (CM and UM, respectively), renal cell carcinoma (RCC), and melanocytic BAP1-mutated atypical intradermal tumor (MBAIT). This evidence concerns the gene BAP1 and cutaneous mastocytosis.