[1594] Choledochal Cysts: A Clinicopathologic Study of 36 Cases with Emphasis on the Morphologic and the Immunohistochemical Features of Premalignant and Malignant Alterations

N Katabi, V Pilarisetty, M D'Angelica, DS Klimstra. Memorial Sloan-Kettering Cancer Center, NY, NY

Background: Choledochal cysts (CDCs) are rare congenital dilatations of the biliary tree. Metaplasia, dysplasia, and carcinoma may develop in CDCs with significant frequency. Therefore, the aim of this study was to focus on neoplastic changes in CDCs and to characterize their morpholologic and immunohistochemical features.
Design: 36 CDCs were identified in the files of MSKCC from 1990 - 2008. Cases were subjected to clinical, histopathologic, and immunohistochemical analyses.
Results: The mean age of pts was 36 (11-67) yrs; there was a female predominance (30/6). The mean size of cysts was 4.37 (0.9-11.5) cm. The cysts were classified based on the Todani classification: type I, 71%; type II, 8.5%; type IV, 14%, and type V, 5.7%. Metaplasia was found in 14/35 cases (40%), of which 9 were also had dysplasia. Of the 14 cases with metaplasia, 13 showed pyloric gland (PG) metaplasia, 5 intestinal (INT) and 2 squamous metaplasia. Dysplasia was found in 10/35 cases (28.5%), 6 low grade, 2 moderade and 2 high grade. Carcinoma was identified in 5/35 cases (14.3%). The histologic type was poorly differentiated adenocarcinoma in 3 cases, papillary in one and tubular in 2. Three carcinomas were associated with metaplasia and dysplasia. Only 1/18 cases without metaplasia had dysplasia and none had carcinoma (p=00008). There was a trend towards more dysplasia and carcinoma with INT metaplasia (5/6) than PG metaplasia (7/12). There was a trend toward increasing p53 and Ki 67 immunoexpression from metaplasia to dysplasia to carcinoma. Additional imunohistochemical features are listed below.

Normal (n=3)PG (n=12)INT(n=6)Dysplasia (n=8)Carcinoma (n=5)

FU was available on 35 pts (median 26 mos). 4/5 pts with carcinoma were DOD and one was AWD 25 mos after diagnosis. All others were NED except one who developed new cystic lesions.
Conclusions: CDCs are associated with a high rate of dysplasia (28.5%) and carcinoma (14.3%). CDCs show a sequence of tumor progression from metaplasia to dysplasia and carcinoma. This highlights a characteristic feature of biliary carcinogenesis.
Category: Liver & Pancreas

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 196, Tuesday Afternoon


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