Multifocal blue nevus of the prostate: a case report

Blue nevus of the prostate is rare and is most commonly discovered incidentally in patients presenting with classic symptoms of prostatic hyperplasia. Only 32 cases have been reported to date in the literature. We describe the first case of multifocal blue nevus of the prostate gland.

A 69-year-old man presented with obstructive urinary symptoms. The preoperative clinical and radiological fndings had shown a massive increase in the volume of the prostate. Suprapubic prostatectomy was performed with good postoperative course. The histopathological examination disclosed benign hyperplasia with large areas characterized by abundant fibromuscular component. In the context of this hyperplasia were observed a dozen foci of pigmented cells measuring 0.1-1 cm in diameter. Histochemical and immunohistochemical stains confirmed the pigment as melanin.

A review of the literature shows that the blue nevus of the prostate is an incidental finding and is most often associated with a benign disease of the prostate, as indeed occurred in our case. All the cases reported are monofocal. Ours is the first reported multifocal case and, as the material has not been fully sampled, consists of at least 12 different outbreaks of varying sizes. Even in our case blue nevus was asymptomatic, and the patient showed no symptoms related to the same blue nevus.