Does Focal Nodular Hyperplasia Predispose to Metastatic Growth of Renal Cell Carcinoma-A Surgical Dilemma

Introduction: Focal nodular hyperplasia is a benign liver disease usually treated conservatively. However, in the setting of a previously resected renal cell carcinoma (RCC) a liver mass with imaging characteristics of focal nodular hyperplasia (FNH) raises a surgical dilemma. Case report: Four years after an initial right nephrectomy for stage I RCC and concurrent oncocytoma, a 72 year-old Caucasian male presented with a liver lesion. Imaging studies raised a question of differential diagnosis between FNH and metastatic RCC. Given the facts, firstly that the radiological findings were suggestive of FNH, secondly that the lesion of the liver was a new finding four years post-resection of the RCC and third that co-existence of FNH and metastatic disease have been reported but the age and sex of the patient were not compatible with the epidemiology of FNH the patient underwent liver resection. Histopathological findings were consistent with FNH and nests of malignant cells compatible with RCC were found in the lesion.