[936] Collagenous Micronodules in Prostate Cancer Revisited: Are They Solely Associated with Gleason Pattern 3 Adenocarcinomas?

MiJin Kim, Mukul K Divatia, Jae Y Ro. College of Medicine, Yeungnam University, Daegu, Korea; Genomic Medicine, Methodist Hospital, Houston, TX

Background: Collagenous micronodules are microscopic stromal eosinophilic fibrillar collagenous nodules of uncertain pathogenesis seen in prostatic adenocarcinoma and often associated with intraluminal mucin. Per the 2005 consensus conference, they are categorized as Gleason pattern 3. This study analyzes morphological and clinical features of collagenous micronodules in a large series of radical prostatectomies.
Design: Hematoxylin and eosin stained slides for 129 radical prostatectomies for adenocarcinoma with collagenous micronodules performed in 667 cases from January 2010 to December 2011 at The Methodist Hospital were examined. Features evaluated in conjunction with collagenous micronodules include mucin secretion, glomerulation, cribriform growth pattern, circumferential perineural invasion, extraprostatic extension and associated Gleason patterns. Clinical factors studied include patients' age, tumor size and location, nodal and seminal vesicle status.
Results: Collagenous micronodules were identified in 19% of all radical prostatectomies. The age range was 43 - 72 years (mean 61). Almost all tumors were located in the peripheral zone (98%) as single or multiple lesions. The tumor size range was 0.5 - 4.0 cm (mean 1.7). Round to oval collagenous micronodules were present in focal or aggregated forms. The nodules were intraluminal or formed subepithelial deposits bulging into the glandular lumina. Most cases (96%) were identified in association with intraluminal mucinous secretion. A cribriform Gleason score 4 growth pattern was associated in 82%. The micronodules were associated with glomerulation (42%) and amphophilic luminal secretion (59%). 88 cases (68%) showed tumor foci with Gleason pattern ≥ 4 in close association with collagenous micronodules. Extraprostatic extension (16%), seminal vesicle involvement (7%) and nodal metastasis (2%) were accomapnying findings.
Conclusions: Collagenous micronodules are frequently seen in peripheral zone prostatic adenocarcinoma in association with mucinous secretion, cribriform growth pattern, Gleason grade 4, and extraprostatic invasion. This study suggests that collagenous micronodules are associated with Gleason pattern 4 warranting reappraisal as a feature seen in pattern 3. Further studies are required to determine the prognostic significance of prostatic adenocarcinoma with collagenous micronodules.
Category: Genitourinary (including renal tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 160, Monday Afternoon


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