[1562] Squamous Cell and Adenosquamous Carcinomas of the Gallbladder: Clinicopathologic Analysis of 34 Cases

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

Background: The information in the literature on squamous cell (SCCs) and adenosquamous carcinomas (ASCs) of the gallbladder (GB) is highly limited. This study, which comprises the largest number of patients to date, was undertaken to better define the clinicopathologic characteristics of these tumors.
Design: 606 resected invasive GB carcinomas were reviewed. 41 cases (6.7%) showed squamous differentiation. Those without any identifiable glandular-type invasive component was classified as pure SCCs (8 cases) and those with the squamous component constituting 25-99% of the tumor as ASCs (26 cases). Remainders were excluded as carcinoma with focal squamous change (7 cases).
Results: Clinical Features: F/M=4.3 (vs 3.8 in ordinary carcinomas; OCs). Mean age=65 (vs 64 in OCs). Pathology: Mean tumor size=3.1 cm (vs 2.7 cm in OCs). 65% (17/26) of ASCs had focal keratinization, while others were poorly differentiated; however, 90% (7/8) of pure SCCs had substantial keratinization including pearl formation and dyskeratotic cells. 32% (11/34) of all cases also revealed squamous change in the adjacent mucosa. 6 cases had sarcamotoid appearance, 5 comedo-like necrosis; 5 focal clear cell change (1 with renal cell carcinoma-like pattern); 3 microcyst formation; 1 sebaceous differentiation and 1 goblet cell change. Tumor giant cells were identified in 29% of ASCs/pure SCCs (vs 10% in OCs; p=0.02). Peritumoral eosinophils were also more common in pure SCCs (51% vs 6% in OCs; p=0.001). The incidence of vascular and perineural invasion were 76% and 32%, respectively (vs 72% and 48% in OCs). 5 of 7 metastatic lymph nodes available for our examination had squamous areas (3 ASCs and 2 pure SCCs.) Outcome: Follow-up was available in 31 patient: 25 died of disease (median=5, range: 0-20 mos), 6 were alive (median=64, range: 5-112.5 mos). Overall median survival (5.4 mos) was worse than that of OCs (11.4 mos, p=0.01).
Conclusions: Squamous differentiation is noted in 6.7% of GB carcinomas. The incidence of ASC (defined as 25-99% of the tumor being squamous) is 4.3%, and that of pure SCC (without any documented invasive glandular component) is 1.3%. Pure SCCs often show prominent keratinization. The overall prognosis of ASC/SCC appears to be even worse than that of OCs. Most patients die within a few months; however, those few alive beyond 2 years might experience long term survival.
Category: Liver & Pancreas

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 209, Monday Morning


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