Primary melanoma of the bladder: a case report and review of the literature.

Primary bladder melanomas are rare and aggressive neoplasms. We herein described a new case and performed a review of the literature. We present the case of a 81-year-old woman with a primary mucosal melanoma of the bladder after a history of acral melanoma (KRAS mutated) and lentigo maligna of the forehead. Using PubMed, we found that in literature 38 cases were described. In our patients, during a transurethral resection (TURBT), two bladder lesions were detected. The histologic exam revealed a malignant melanoma, Mib1/ki67: 10-12%, PDL1 <1%. No BRAF, NRAS or KRAS mutations were detected. She subsequently underwent a transurethral revision of the trigone and a partial cystectomy of the dome with bilateral pelvic lymph node dissection. Microscopical findings showed a residual 5 mm non-muscle-invasive melanoma of the bladder, with negativity of the surgical margins and of the 17 pelvic lymph nodes. No adjuvant treatment was proposed. To date the patient is disease-free. Primary bladder melanoma carries a poor prognosis and poses a therapeutic challenge to clinicians who manage patients with this rare condition. In our experience the multidisciplinary approach for the diagnosis and management of this rare cancer is mandatory.