[1593] Non-Neoplastic Polyps of the Gallbladder: Incidence, Histologic Types, and Clinicopathologic Associations in an Analysis of 162 Cases.

Courtney E Vance, Juan Carlos Roa, Nevra Dursun, Oscar Tapia, Leslie Ducato, Burcu Saka, Kee-Taek Jang, Hector Losada, Juan Sarmiento, Sudeshna Bandyopadhyay, NVolkan Adsay. Emory, GA; UFRO, Temuco, Chile; WSU, MI

Background: The data on the pathologic characteristics and clinicopathologic associations of non-neoplastic GB polyps (NNP) is highly limited.
Design: Cases that had been designated as “polyp” in the authors' files were retrieved. Additionally, 2206 consecutive cholecystectomies were systematically analyzed.
Results: 162 NNPs were identified with an incidence of 2.2% (46 in 2206 systematically reviewed GBs). Only 10 (6%) were >1.0 cm (the cut-off used widely as cholecystectomy indication). In comparison, identified in the same review were 92 intracholecystic papillary tubular neoplasms (ICPN) and 29 polypoid invasive carcinomas ≥1.0 cm. The average age of NNPs was 52 (vs 64 for ICPN and 47 for cholecystitis); F/M=2.6. Histopathologic types: 1. Fibromyoglandular polyp(n=90;Fig A): Broad-based polyps composed of lobules of small pyloric-like glands separated by fibroblastic stroma with variable amounts of smooth muscle. They were small (mean=0.4 cm; largest, 1.3 cm), often multiple(48%), and almost always associated with stones (98%) and significant inflammation (77%). Dysplastic changes were identified in 14%. 2. Cholesterol-type polyps(n=64,Fig B): Pedunculated, arborizing papillary lesions lined by normal GB epithelium, with edematous cores mostly devoid of glands and often (85%) but not always showing cholesterol-laden macrophages. Only 25% were associated with cholesterolosis in the uninvolved GB. 33% occurred in males. 3% showed overt dysplastic changes as a focal finding. 3. Inflammatory and stromal polyps: 2 granulation tissue, 2 xanthogranulomatous, and 2 lymphoid.

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Conclusions: I. NNPs are seen in 2.2% of cholecystectomies but most (93%) are small (<1 cm) and incidental. II. Among clinically significant (≥1 cm) polyps, only 8% are NNPs. III. Focal dysplasia is seen in 9% of otherwise classic NNPs, and some show transitional features with ICPN, suggesting a progression phenomenon. IV. Cholesterol-type polyps are defined by a distinctive morphology rather than cholesterolosis. V. What we propose to designate as fibromyoglandular polyps are distinctive lesions that are often multiple, associated with stones and inflammation, and harbor focal dysplasia in 14%.
Category: Liver & Pancreas

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 194, Wednesday Morning

 

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