Blue Nevus of the Prostate: A Report of Two Cases and Review of the Literature

Abstract Pigmented lesions of the prostate are very rare and include melanosis, blue nevus, and malignant melanoma. Of these lesions, blue nevus (also known as pigmented melanocytosis or pigmentary nevohyperplasia) is the most frequently reported one. It is morphologically similar to its much more common cutaneous counterpart and composed mainly of heavily pigmented spindle cells within the prostatic stroma. It is often discovered incidentally in needle biopsies, transurethral resection of the prostate, or prostatectomy specimens performed for prostatic cancer or benign prostatic hyperplasia. It is a benign lesion with no potential for malignant transformation. Recognition of this entity is important because of the differential diagnosis with the much rarer malignant melanoma involving the prostate. The pathologic features and differential diagnosis with relevant literature review are discussed in this report.