1. Cystic Biliary Hamartomas: one protruding into large bile duct in 60 year-old male patient with advanced gastric carcinoma 소화기병리연구회

2. ▷ Subcapsular multiseptated mass of low density (3.8cm x 3.6cm) ▷ Central lobulated mass of low density (3.3cm x 2.4cm) ▷ Dilatation of left intrahepatic bile ducts 소화기병리연구회

4. 3.0cm 3.5cm x 1.5cm Polypoid mass at bifurcation of segment 2 & 3 branch ducts

5. Left lobe of Liver - Gross Finding ▷ Non-cirrhotic liver ▷ A polypoid lesion (3.5cm x 1.5cm; soft & white) protruding into the dilated large bile duct. ▷ A subcapsular cystic mass, multilocular, (3cm x 3cm) found at 0.3cm apart from the intraductal polypoid lesion. 소화기병리연구회

8. SMA

9. Left lobe of Liver - Microscopic Finding ▷ Composed of multiple, variable-sized cysts lined by flat or columnar, some mucinous epithelium of the biliary type. ▷ Many gland structures between cystic spaces. ▷ Fibrous and slightly edematous stroma between cysts and glands with some smooth muscle fibers. ▷ N o compact ovarian-like stroma present. ▷ The background liver is not cirrhotic and shows mild cholestasis. 소화기병리연구회

10. Pathological Diagnosis: ► Cystic biliary hamartoma protruding into large bile ducts ► Hamartomatous polyp of intrahepatic bile duct, probably belonging to multicystic biliary hamartoma ( Diagnosis proposed by Drs. Nakanuma Y, Sasaki M and Zen Y) 소화기병리연구회

11. Comments ► Overall appearance suggests that it might be hamartomatous and not a true neoplasm. ► Resembles cysts of the peribiliary gland origin. ► This case is unique in terms of growing into the dilated intrahepatic bile ducts. ► Otherwise resembles multicystic biliary hamartoma that coined by Dr. Nakanuma. 소화기병리연구회

12. In this report, we presented 3 cases of unusual hamartomatous nodules of the liver. These nodules were located around hepatic capsule of the left hepatic lobe and characteristically protruded from the liver. Histologically, these nodular lesions consisted of ductal structures, periductal glands, and fibrous connective tissues containing blood vessels. Smooth muscle bundles focally surrounded ductal structures. Bile-like materials were observed within some ducts. Two cases were associated with xanthogranulomatous inflammation around bile-like materials, and this inflammatory process extended from ductal lumens to periductal connective tissues. In contrast, the remaining case, which was not associated with inflammation, showed a honeycomb appearance. Ductal epithelium and periductal glands resembled biliary epithelium and peribiliary glands, respectively, and they also expressed biliary-type cytokeratins such as cytokeratins 7 and 19. These nodules shared pathologic characteristics of ciliated hepatic foregut cysts, such as their location (around the falciform ligament) and periductal smooth muscle bundles, but did not fulfill the diagnostic criteria (no ciliated cells and multilocular lesions). These hamartomatous nodules of the liver did not fit into any of the described categories of hepatic nodular lesions. At present, we speculate that these lesions might be related to developmental abnormalities of the biliary tract or embryonal foregut. [Hum Pathol 2006 Mar;37(3):339-44] Multicystic biliary hamartoma: a hitherto undescribed lesion Zen Y, Terahata S, Miyayama S, Mitsui T, Takehara A, Miura S,Terahata SMiyayama SMitsui TTakehara AMiura S Nobata KNobata K, Kitao A, Kakuda K, Kiyohara K, Nakanuma YKitao AKakuda KKiyohara K

15. Overgrowth of VMC Hepatic von Meyenburg complex simulating adenocarcinoma 소화기병리연구회

16. SS07-43719