Choroidal melanoma and polydactylous onychopapilloma leading to diagnosis of BAP1 tumor predisposition syndrome.

Polydactylous onychopapillomas as a cutaneous clue leading to diagnosis of a BAP1 syndrome, confirmed by germline testing

BAP1 tumor predisposition syndrome (BAP1-TPDS) is autosomal dominant, associated with uveal melanoma and multiple cancers, and likely underdiagnosed. Polydactylous onychopapillomas have recently been recognised as an associated phenotype. The authors describe a 62-year-old man with choroidal melanoma and multiple onychopapillomas, plus a suggestive family history. Tumor profiling (Class 2, PRAME-negative) and sequencing identify GNAQ and BAP1 variants (a splice-site variant at high allele fraction); germline testing confirms a hereditary BAP1 variant, establishing the BAP1-TPDS diagnosis.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

A useful case report reminding us that a subtle cutaneous sign — onychopapillomas — can be the gateway to a major tumor predisposition syndrome. Its value is mainly educational and semiological: examine the nails and consider germline BAP1 testing in the setting of uveal melanoma.

Analysis by Dr Thibaut Benquey