Biliary cystadenocarcinoma diagnosed by liver biopsy performed under ultrasonographic guidance

A case of a 60-yr-old man with biliary cystadenocarcinoma is reported. By needle biopsy of a cystic lesion performed under ultrasonographic guidance, overt malignant tissue could be obtained successfully. Histologic examination on autopsy material revealed that the tumor arose from preexisting benign liver cysts. The tumor showed a feature of well-differentiated, mucin-producing papillary adenocarcinoma in the primary site while, in the metastatic foci, it produced solid cell clusters with a tendency toward the differentiation into squamous cells.