Urinary Bladder Melanosis Diagnosed Simultaneously With Urothelial Carcinoma: A Case Report and Literature Review

Abstract

Melanosis is a rare entity described as brown-black tissue pigmentation secondary to melanin deposition. Presented here is the third reported case of melanosis diagnosed simultaneously with urothelial carcinoma of the bladder. This is only the sixth case associating melanosis with malignancy. The patient is a 78-year-old man who presented with lower urinary tract symptoms and on cystoscopy, was noted to have diffused brown-black bladder pigmentation. Initial pathology showed squamous cell carcinoma with melanosis present. The patient underwent robotic cystectomy with ileal conduit and on final pathology, had urothelial carcinoma with squamous differentiation. A literature review was performed for both benign-associated and malignant-associated melanosis. The review elucidated that melanosis may herald malignancy in 16% of available reported cases, suggesting even a patient with benign melanosis should undergo surveillance.