[912] Paraganglia of the Prostate in Radical Prostatectomy Specimens

KP Maniar, PD Unger, DB Samadi, GQ Xiao. Mount Sinai Hospital, New York, NY

Background: Paraganglia are a collection of neuroendocrine cells which are uncommonly reported in the genitourinary system. In this study, we evaluated over 500 robotic assisted radical prostatectomy specimens performed over one year for the presence and location of paraganglia. Awareness of this tissue is important, as it can mimic prostatic adenocarcinoma.
Design: 573 radical prostatectomy specimens were collected from 2008 to 2009, with 75-100% of the tissue submitted for evaluation. Immunochemistry was performed on sufficient material. The cases were categorized by location and patient age.
Results: A total of 35 cases of paraganglia in 573 specimens were found (6.1%). The number of cases by age were as follows: <50 - 3 cases, 50-59 - 12 cases, 60-70 - 17 cases, and >70 - 3 cases. Five cases showed multiple paraganglia, leading to a total of 41 paraganglia, located as follows: 2 in prostatic parenchyma, 5 in the pseudocapsule, and the remainder in extraprostatic soft tissue. One extraprostatic paraganglion in the superior anterior region was involved by prostatic adenocarcinoma. The majority of the paraganglia were located posteriorly (23 posterior, 14 anterior, 4 not indicated), and superiorly (28 superior, 10 mid, 3 inferior). The foci ranged in size from 0.1-1.1mm, and were frequently seen associated with nerves and ganglia. Although the majority were too small for immunohistochemistry, one case demonstrated positivity for chromogranin, synaptophysin, and S100, and negative staining for PSA.
Conclusions: In this study, paraganglia were present in 6.1% of radical prostatectomy specimens, in comparison with 8% in a previously reported small series of 100 cases. The characteristic “zellballen” pattern of paraganglia, with a rich intervening capillary network, are helpful morphological clues in their recognition. In difficult cases, immunohistochemistry is helpful if sufficient material is present. Recognition of this benign tissue is important in distinguishing it from prostatic adenocarcinoma. This becomes especially significant when the paraganglia are located external to the prostatic pseudocapsule; misidentifying these foci as tumor may lead to falsely diagnosing the patient with a higher stage of disease. Additionally, the characteristic appearance of paraganglia most closely resembles Gleason pattern 4 or 5 prostatic adenocarcinoma, leading to the possibility of assigning the tumor a falsely higher Gleason score. Awareness of this entity should allow the pathologist to avoid such overdiagnosis.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 132, Monday Afternoon

 

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