Metastatic Melanoma in Bladder

Malignant melanomas involving the urinary bladder are usually metastatic lesions. Primary melanomas of the bladder are exceedingly rare. The image shows a sheet of poorly-differentiated tumor cells in the lamina propria beneath a denuded urothelial surface. The patient had history of melanoma removed from the back several years prior to her presentation with gross hematuria. The diagnosis of metastatic melanoma was confirmed with immunohistochemical stains.