[704] Intraampullary Papillo-Tubular Neoplasms (IAPN): A Clinicopathologic Analysis of 85 Cases of Mass-Forming Preinvasive Neoplasm Occuring within the Ampulla

N Ohike, GE Kim, I Coban, T Tajiri, A Krasinskas, S Bandyopadhyay, O Basturk, T Morohoshi, Y Shimada, D Kooby, C Staley, NV Adsay. Emory U, GA; USCF, CA; Showa U, Tokyo, Japan; U of Pittsburg, PA; WSU, MI; NYU, NY; Georgia Tech, GA

Background: There has been no systematic analysis or uniform terminology for mass-forming preinvasive neoplasms occurring within the ampulla, which we refer to as IAPN.
Design: 85 resected IAPNs were analyzed. Cell lineage was designated intestinal (IN) or gastric/pancreatobiliary (GPB) for preinvasive component, and intestinal (InvIN) or pancreatobiliary (InvPB) for associated invasive carcinoma (inv ca).
Results: M/F=58/26; mean age 64; mean size 2.7cm. I. 27% had papillary growth, 57% papillary & tubular and 20% tubular. II. 8% had no high-grade dysplasia, 38% had focal, 27% substantial and 26% extensive. III. 75% were IN; 25% GPB. Sensitivity & specificity of cell lineage markers: IN: CDX2(74%, 89%), MUC2(31, 100) and CK20(82, 72); GPB: MUC1(67%, 92%), MUC5AC(56, 95), MUC6(39, 97), and CK7(94, 46). 40% were CK7+/CK20+; 64% were P53+ (IHC). IV. 75% had inv ca: 53% were InvIN, 41% InvPB and 4% others. Invasion was <1 cm in 24 cases and >2cm in 16. Preinvasive cell lineage persisted into invasive component: All InvIN arose from IN and 62% of InvPB from GPB. V: Overall, IAPNs had better survival than other ampullary carcinomas with 3 and 5-yr surv rates as 71% and 44% vs 44 and 28, respectively. Even those with invasion had a significantly better survival (3-yr 69 vs 44%, p<0.01). Although IN and InvIN showed a trend for better prognosis than GPB and InvPB; the difference did not reach statistical significance (5-yr; p=0.25, p=0.07, respectively). Tumor budding (58%) had a significantly worse prognosis (p<0.05).
Conclusions: Intraampullary neoplasms characterized by papillary and tubular preinvasive growth, which we term IAPNs, are analogous to pancreatobiliary IPMNs or intraductal tubulopapillary neoplasms, by showing variable cell lineages & spectrum of dysplastic changes (adenoma-ca sequence). Morphologic classification of IAPNs into IN vs GPB is also supported by IHC panel, with CDX2/MUC2 as markers for IN and MUC1/MUC2/MUC5AC for GPB. CK7/CK20 profile is non-discriminatory. IAPNs are indolent neoplasms; even those with invasion have a better prognosis than pancreatic or other ampullary carcinoma. Tumor budding is associated with aggressive behavior.
Category: Gastrointestinal

Monday, March 22, 2010 1:00 PM

Poster Session II # 92, Monday Afternoon

 

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