Malignant melanoma in neo-bladder urinary cytology: a brief report.

Malignant melanoma has an unusual predilection for metastasis to the small bowel, sometimes several years after the original diagnosis. In patients who have had a cystoprostatectomy followed by an ileal conduit, metastatic melanoma to the ileal conduit can present in urine cytology. We present a rare case of metastatic malignant melanoma in neo-bladder urine in a patient who had undergone a cystoprostatectomy for high grade urothelial carcinoma of the bladder and prostatic adenocarcinoma of Gleason grade 3+3 and two excisional procedures for cutaneous malignant melanoma. He presented with persistent hematuria and urinary tract infections unresponsive to treatment. Urine cytology revealed single large atypical cells, with large nuclei, prominent nucleoli, and cytoplasmic melanin pigment. Subsequent surgical resection revealed two areas of metastatic melanoma in the ileum, one of them being in the ileal conduit. The tumor cells were immunoreactive for S-100 protein, Melan-A, and HMB-45 and were negative for CAM5.2 and cytokeratins 7 and 20.