title: Biliary adenofibroma with ominous features of imminent malignant changes.
abstract: Biliary adenofibroma (BAF) is a rare, benign liver tumor. Herein, we report a case of BAF with histological features of imminent malignant changes. Ultrasound and CT revealed a solid 2.5-cm mass in the right liver lobe. The patient was asymptomatic and had no past medical history including liver disease. A general examination that included the abdomen and the laboratory data were normal. Because of the increase of its size, this tumor was surgically resected. Grossly, a 3.5-cm nodular mass abutted on the hepatic capsule was found, and its cut surface showed a well-circumscribed, whitish, and firm lesion that showed microcystic changes in the periphery and solid changes in the central parts. Histologically, the tumor showed a proliferation of tubulocystic structures embedded in a fibrous stroma. Microcysts were prevalent in the periphery, while tubular components with abundant fibrous stroma were in the central parts. The tubules were variably dilated and branched. This case closely resembled the previously reported cases of BAF, except that there were complicated papillary projections with fine fibrovascular cores in some of the microcysts and that the epithelial component in papillary projections showed dysplastic changes and increased cellular proliferative activities, implicating ominous features of imminent malignant changes. These dysplastic and papillary changes may be an intermediate lesion leading to malignancy, which have occasionally been reported in BAF.
authors.affiliation: Section of Diagnostic Pathology, Department of Pathology, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, 920-8641, Japan, atsutsui@staff.kanazawa-u.ac.jp.
authors.forename: Akemi
authors.initials: A
authors.lastname: Tsutsui
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Bando
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.forename: Hidenori
authors.initials: H
authors.lastname: Miyake
authors.forename: Seiko
authors.initials: S
authors.lastname: Sawada-Kitamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibata
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kakuda
authors.forename: Kenichi
authors.initials: K
authors.lastname: Harada
authors.forename: Motoko
authors.initials: M
authors.lastname: Sasaki
authors.forename: Yasuni
authors.initials: Y
authors.lastname: Nakanuma
mesh_terms: D000232:Adenofibroma / Q000473:pathology*; D000368:Aged; D001650:Bile Duct Neoplasms / Q000473:pathology*; D001653:Bile Ducts, Intrahepatic; D005260:Female; D006801:Humans