[635] Intravesicular Papillary-Tubular Neoplasm (IVPN) as a Unifying Category for Mass-Forming Preinvasive Neoplasms of the Gallbladder: An Analysis of 87 Cases

N Dursun, JC Roa, O Tapia, A Cakir, I Coban, O Basturk, D Akdemir, J Sarmiento, H Losada, NV Adsay. Emory U, GA; U de La Frontera, Temuco, Chile; NYU, NY; Ohio Northern U, OH

Background: Mass-forming (polypoid) preinvasive papillary and tubular neoplasms of gallbladder (GB) mucosa, which we propose to refer to as IVPN, have been poorly characterized.
Design: 87 IVPNs, defined as non-invasive neoplasm forming a well-defined exophytic mass measuring >1cm (the criterion employed for clinical significance in pancreatic IPMNs, and cholecystectomy indication for GB polyps), were analyzed.
Results: M/F=20/62, mean age 64. Median tumor size=2.1 cm (range, 1-7.7). I. Variable growth patterns were evident: Papillary (46%), tubulopapillary (39%), and tubular (14%). II. Various cellular lineages including intestinal (17%), gastric (16%), pancreatobiliary (30%) could be discerned; however, transitional/mixed forms were common (36%). III. 4% of the lesions had no high-grade dysplasia (HGD), while 30% had focal, and 66% extensive. HGD was commonly extensive in papillary examples (10/12) but not in tubular ones (5/12). However, even the cases that would have qualified as “pyloric gland adenoma” (previously considered an innocuous lesion), had at least focal HGD (14/16), and 75% occurred in association with invasive carcinoma (12/16). Conversely, some cases that might have qualified as “papillary ca” displayed foci of low-GD (18/52) or had no identifiable invasion (7/52). IV. 75% had an associated invasive ca (ordinary adenoca-55/63; others-8, including 3 mucinous, 2 neuroendocrine). Invasion was focal in 4/63 and extensive in 36/63. Among systematically analyzed invasive carcinomas, IVPN was detected in 10% (63/606). V. 1- and 3-yr actuarial survival were 92% and 77% for non-invasive IVPNs vs 68% and 45% for IVPNs with an associated invasive ca (p=0.05). However, even invasive ones had a better clinical outcome than ordinary GB carcinomas (3-yr survival 45% vs 28%; p<0.001).
Conclusions: IVPNs are analogues of mass-forming preinvasive neoplasms in other organs such as pancreatobiliary IPMNs, showing variable cellular lineages, spectrum of dysplasia (adenoma-carcinoma sequence), and a mixture of tubular-papillary growth patterns, often with significant overlaps, warranting the classification of these lesions under one unified category. These are relatively indolent neoplasia with significantly better prognosis than ordinary GB carcinomas; however, invasive examples can be fairly aggressive, and even non-invasive ones may be fatal.
Category: Gastrointestinal

Monday, March 22, 2010 1:00 PM

Poster Session II # 90, Monday Afternoon

 

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