[1002] Perinucleolar Clearing (PNC) with Macronucleoli Is Not a Feature of Some Benign Mimics of Prostate Cancer

Hemamali Samaratunga, Dinithi Samaratunga, John Yaxley, Joanna Perry Keene, Diane Payton, Brett Delahunt. Aquesta Pathology, Brisbane, QLD, Australia; Royal Brisbane Hospital, Brisbane, QLD, Australia; Wellington School of Medicine and Health Sciences, Wellington, Otago, New Zealand

Background: Nucleolar prominence has been found to be a useful feature in the diagnosis of prostate cancer. However, benign mimics also display prominent nucleoli. Nucleolar characteristics in these lesions on needle biopsy have not been adequately studied.
Design: 100 needle biopsies with ≤ 20% Gleason score 3+3=6 prostatic adenocarcinoma (including 38 with only small foci or <5%) in one core were compared with 20 cases of adenosis and 37 of partial atrophy for presence of prominent but small nucleoli identified at x400 magnification and for very large, often eosinophilic nucleoli (macronucleoli) including those with perinucleolar clearing (PNC) easily identified at x100 or x200 magnification. The mean percentages for each were estimated visually and recorded as absent; 0, rare; <10%, frequent; 10-50% and common; >50%.
Results: Carcinoma had prominent nucleoli in 98%, macronucleoli in 65% and macronucleoli with PNC in 46% of cases whereas adenosis had 25%, 0% and 0% and partial atrophy had 32%, 0% and 0% respectively. Macronucleoli and macronucleoli with PNC in cases with only small foci of cancer were 63% and 47% respectively. Prominent nucleoli were frequent or common in 63% of carcinoma, 10% of adenosis and 6% of partial atrophy.
Conclusions: Presence of frequent prominent nucleoli suggests a more likely diagnosis of carcinoma. Macronucleoli with or without PNC in a focus argue against a benign diagnosis. Typically, other features of carcinoma in these cases will assist with a cancer diagnosis. In cases with limited such features, an outright benign diagnosis is not warranted
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 163, Wednesday Afternoon


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