[Bladder metastasis of malignant melanoma: report of a case].

Objectives: To report one case of malignant melanoma metastasis into the urinary tract, diagnosed after excision of the primary lesion.

Methods: Case of a 75 year old male with history of malignant melanoma in the scapular region excised 7 years before who presents with lower urinary tract symptoms (LUTS), hematuria and a hypogastric mass, 12 cm in diameter, located superficially and anterior to the bladder. He underwent partial cystectomy for excision of the mass, prostate adenomectomy and lithiasis extraction.

Results: Pathological study showed neoplasic cell proliferation with tendency to form sparse round nests or sheaths; cells had wide, polygonal cytoplasms and occasionally melanocitic pigment. Protein S-100 detection by Immunohistochemical tests was positive, being the final diagnosis malignant melanoma metastasis.

Conclusions: Bladder metastatic disease is unusual and rarely clinically evident. Nevertheless, it is frequent for bladder metastases to be caused by melanoma. Bladder metastatic lesions are rarely symptomatic, although approximately 15% of the cases are symptomatic, being hematuria the most common presentation. Although radical cystectomy seems to be the treatment of choice in potentially curable patients with solitary metastasis, to date no patient has survived more than three years, demonstrating the aggressive natural history and ominous prognosis of this disease.