Benign biliary inflammatory pseudotumor mimicking a Klatskin tumor.

Most biliary tumors at the liver hilum are malignant and, when possible, require radical surgical resection. However, few rare benign lesions exist, for which the differential diagnosis with malignancy is important in order to avoid aggressive surgical treatment. This is a retrospective case report. We report on two patients suffering from presumed inflammatory pseudotumor of the main biliary convergence, mimicking a Klatskin's tumor. Complete multidisciplinary work-up in a specialized hepatobiliary centre, including tumor markers, imaging studies and FDG-PET were strongly in favor of malignancy. The benign nature of the lesions was only suspected on the natural radiological evolution during the time waiting for surgical resection, with progressive spontaneous disappearance of tumor masses. Therefore, we were able to avoid extensive hepatobiliary surgery in both patients, including performance of an extended right hepatectomy. However, the patients had portal vein embolization as a first step in treating the disease, hopefully with no long-term consequences on patient status and liver function tests. Clinicians should be aware that tumors arising at the hepatic bifurcation are not always malignant, even if it is the most frequent cause. Despite extensive multidisciplinary work-up, there are still persisting difficulties in this differential diagnosis.