[Does primary melanoma of the bladder exist?].

Primary melanoma of the urinary bladder is a rare neoplasm to which very strict diagnostic criteria apply. Although reports of previous cases exist, these criteria have yet to be met. We report a case of a young lady from whom a malignant melanoma of the bladder was resected. This was presumed to be primary as detailed investigation failed to find any other site from which metastases could have originated. We discuss the diagnostic criteria of this entity and stress the difficulty in conclusively demonstrating that, despite some of these criteria being met, a lesion such as this is primary in origin. This case could be the longest surviving patient with primary melanoma of the bladder, however we will never be able to prove that spontaneous regression of an undiagnosed extravesical primary malignant melanoma did not occur.