Biliary deposition of Liesegang rings presenting as a polypoid mass in the liver: previously unrecognized lesion.

Liesegang rings (LR) are acellular, laminated structures that may be deposited within and around cysts and inflamed or necrotic tissue. Previous reports have shown that the kidney and breast are commonly affected organs of LR. Herein is reported a rare case of biliary deposition of LR presenting as a tumor-like polypoid mass in the liver. A 70-year-old man was found to have a cystic lesion, measuring 3.0 cm in diameter, in the lateral segment of the liver. The lesion was accompanied by a solid mass, 1.8 cm in diameter, within the cystic cavity. Lateral segmentectomy of the liver was performed because clinical examinations could not exclude the possibility of hepatobiliary cystadenoma or cystadenocarcinoma. Pathology of the resected specimen indicated a soft polypoid mass, connecting to the cystically dilated bile duct with elongated stalk-like structures. Histologically the surface of the mass was covered by non-neoplastic biliary-type epithelium. Beneath the epithelium, extensive deposition of numerous ring-like laminated structures, which exhibited an identical appearance to LR, was observed. This is a unique and previously unrecognized lesion involving the occurrence of LR deposition in the hepatobiliary tracts, which further formed a grossly visible mass resembling a hepatic tumor.