[862] Ectopic Prostatic Tissue: Histogenesis and Histopathologic Characteristics

SK Halat, JN Eble, DJ Grignon, S Lacy, R Montironi, GT MacLennan, A Lopez-Beltran, PH Tan, LA Baldridge, L Cheng. Indiana University, Indianapolis; Polytechnic University of the Marche Region (Ancona), Ancona, Italy; Case Western Reserve University, Cleveland; Crodoba University, Cordoba, Spain; Singapore General Hospital, Singapore, Singapore

Background: Ectopic prostatic tissue has been described in various organs, including bladder, seminal vesicles, epididymis, anal canal, uterus and cervix. Various theories exist regarding its origin, including persistent embryonic structures, misplaced tissue, or metaplasia from one tissue type to another in response to irritating stimuli. The present study was conducted to evaluate its histological and immunohistochemical characteristics in order to better define its origin and nature.
Design: We studied 21 cases found in our surgical pathology archives from 1987 to 2008. All patients were men, ranging in age from 30 to 84 years old (mean age 46). Tissue sections were immunostained using antibodies against PSA, PSAP, P501S, 34βE12, p63, AMACR, CK18, and CD10.
Results: In 86% (18/21) of the cases, the ectopic prostate tissue was located in the bladder; in the remaining cases it was located in the urethra. In no case was the ectopic prostate tissue contiguous with the prostate gland. In 66% of the cases (14/21), no significant inflammatory or reactive/reparative changes were identified in the adjacent tissue. Immunohistochemical stains for PSA, PSAP, and P501S were positive in the glandular epithelial cells of all cases. Stains for 34βE12 and p63 confirmed the presence of basal cells in all cases. There was no overexpression of AMACR in any of the cases. There was cytoplasmic luminal staining for CD10 and cytoplasmic staining for CK18 in acinar cells in 20 cases. In cases in which follow-up data were available, no patient was found to have residual or recurrent ectopic prostatic tissue, and no patient developed prostatic adenocarcinoma.
Conclusions: Ectopic prostate tissue is occasionally encountered in the lower urinary tract, most commonly in the bladder and urethra of males. Foci of ectopic prostate tissue exhibit all the characteristics of benign prostatic glands, including the presence of secretory and basal cell layers and immunohistochemical profiles indistinguishable from that of normal benign prostate tissue. The lack of inflammation in the majority of these lesions suggests that these lesions are likely persistent embryonic structures, rather than reactive metaplastic processes.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 103, Tuesday Afternoon


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