Non‐epithelial neoplasms of the prostate

Abstract

Non-epithelial prostatic neoplasms are infrequent and cover a broad array of entities that include both benign and highly aggressive tumours. Because they are very infrequent, there is often limited understanding of them, and the recognition of these entities, when encountered, may pose a diagnostic challenge, owing to histological overlap between them or their rarity. Most lesions in this category are mesenchymal in origin, such as prostatic stromal tumours arising from specialized prostatic stroma, smooth muscle tumours, both benign and malignant, and solitary fibrous tumours. Less commonly occurring tumours include neural, germ cell and melanocytic tumours that may be derived from cells not normally present in the prostate. Some tumours have well-established extraprostatic counterparts and, when encountered, are more commonly extraprostatic/secondary in origin; these include gastrointestinal stromal tumours and most haematopoietic tumours. The majority of tumours are characterized by a spindle cell pattern with significant overlap in morphological features. In this setting, appropriate use of immunohistochemistry and molecular studies are often necessary for accurate diagnosis, prognosis, or prediction for therapy. This review addresses and updates the clinicopathological features of the entire spectrum of non-epithelial tumours with an approach to the histological diagnosis.

Prostatic melanosis

“…While the presence of melanocytic cells in the prostatic stroma is described as blue nevus, the term melanosis is used when the melanin pigment is seen in the glandular cells and the stroma. [1]…”

“…[1] Histopathologically, dendritic cells loaded with brown-black pigment are observed in the prostatic stroma. In cases with melanosis, melanin pigment is present in the epithelial prostatic gland neighboring dendritic cells, unlike the blue nevus.…”

“…Immunohistochemically, the stromal dendritic cells stain positively for S-100 protein, but negatively for HMB-45. [12345]…”

“…Melanosis, blue nevus, and malignant melanoma are lesions seen in the prostatic tissue, containing melanin pigment. [1]…”

Malignant Mesenchymal Tumor of the Prostate: A Case Report

“…[1] The prognosis of nonepithelial tumors of the prostate is worse compared with epithelial tumors of the prostate and their treatment methods are also different. Leiomyosarcoma is the most common malignant mesenchymal lesion of the prostate observed in adults.…”