Primary Melanoma of the Urinary Bladder: Clinical, Histopathologic, and Comprehensive Molecular Analysis of a Rare Tumor.

Primary melanoma of the urinary bladder is extremely rare and generally has a poor prognosis. The histopathological diagnosis can be challenging as tumors can be unpigmented and of varying morphology. Here we report a rare example of primary urinary bladder melanoma with clinical, imaging, gross anatomical, histopathologic, immunohistochemical, and molecular findings to illustrate the utility of an integrated approach in establishing the diagnosis and guide therapy. A comprehensive, integrated approach, including molecular studies, may be helpful in further establishing an accurate diagnosis and informing therapies of this rare but poorly behaved entity.