A case of biliary adenofibroma of the liver with malignant transformation: a morphomolecular case report and review of the literature.

Background: Biliary adenofibroma is an exceptionally rare benign liver tumor with the potential for malignant transformation. In literature, only 21 cases have been described.

Clinical Presentation: In a healthy 63-year-old woman, a partly solid, partly cystic mass in the left lobe of the liver during a routine ultrasound examination was found. The computed tomography (CT) scan of the abdomen showed a 6.3 × 5.0-cm multilobulated cystic, partly hypervascularized mass in the liver segment IVa, with extension into segments II and IVb. There was no evidence of lymph node or distant metastases. Extirpation of the tumor was indicated by the multidisciplinary tumorboard. Microscopic examination showed a biphasic composed tumor with tubules embedded in fibrous stroma. In addition, there were also areas with pseudopapillary projections, as well as parts with focal cribriform-like growth pattern, which have been indicated as a possible sign of malignant transformation. Additionally, we found two different polymorphisms in the encoded TP53 und KIT in both distinct morphology tumor areas by molecular analysis, which ensured a tumor in malignant transformation. The patient has been alive for 24 months after R0 resection without tumor recurrence. Further investigation of more cases of this rare entity is necessary to proof molecular genesis.

Conclusions: We report a rare case of a biliary adenofibroma with transition to an intrahepatic cholangiocellular carcinoma and present a brief literature review.