Blue Nevus and Melanosis of Prostate

Blue Nevus of the Prostate: Report of Two New Cases with Immunohistochemical and Electron-Microscopic Studies

“…Including the 2 cases reported in this paper, only 21 cases of true BNP have been reported in the literature [1-6, 8, 9, 11-14, 16, 17], with 9 more cases corresponding to MP [5,[8][9][10]12,15].…”

“…The origin of the cells seems to be the neural crest, but the problem actually focuses on the precursor cell from which the blue nevic cell is derived. The first theory hypo thesizes [1,4,5,[8][9][10][12][13][14] that the precursor cells are true mela nocytes entrapped ectopically in the prostate during their migration towards more distal and superficial sites. The other theory suggests a Schwann cell as the origin [ 18,30], The ultrastructural analysis of the tumors shows marked similarities between the melanocytes and the Schwann cells, including incomplete or complete basal cell lamina [31], desmosome-like structures and compound melanosomes, with the only differential feature being the presence or absence of premelanosomes [26,32], The findings of Ghadially [32] and Lovas et al [33] suggest that the melanocytes are the sole type of cell with the capacity of producing premelanosomes, and so the blue nevus would be of melanocytic origin.…”

Melanosis (Pigmented Melanocytosis) of the Prostate Gland

“…The surgical material was fixed in 10% calcium-acetate-buffered formalin, pH 7, embedded in paraplast and stained with hematoxy lin and eosin (HE), periodic-acid Schiff (PAS), Gomori's methenamine silver impregnation, Peris' reaction for Fe", Schmorl's tech- [20] 1972 3 + no pigmented areas observed Langley and Weitzner [21] 1974 1 + dense aggregate of black pigment Rios and Wright [10] 1976 1 + + India ink-like pigment scattered and solid areas Kovi et al [14] 1977 1 + + multinodular aspect Scarani et al [9] 1979 + areas of black pigmentation Aguilar et al [11] 1982 1 Therefore, the term 'pigmented melanocytosis' would appear to describe better such a pathologic condition.…”

Nonepithelial Tumors and Tumor-Like Lesions of the Prostate Gland

“…In retrospective reviews of consecutive prostatectomy specimens, it appears that the combined incidence of melanosis and blue nevi is about 4%. 164,165 Although melanosis appears to be more common than blue nevi, there have been more reports of blue nevi than melanosis. [165][166][167][168][169][170][171][172][173][174][175][176][177][178][179][180] About 20 cases of blue nevi have been reported.…”

“…The origin of the stromal melanocytes is believed to be from cells migrating from the neural crest. 165,[167][168][169] As for the origin of the epithelial melanosis, it is believed to be just passive transport of melanin pigment from stromal cells. 170 Based on the absence of S100-positive cells within the epithelium of the prostate tissue from different age groups as reported by Lew 176 and the presence of only mature melanosomes by electron microscopy, one tends to favor the passive transport of melanin pigment by epithelial cells.…”