Focal nodular hyperplasia of the liver associated with portal vein agenesis: a morphological and immunohistochemical study of one case and review of the literature.

Congenital absence of portal vein (CAPV) is a rare malformation. To our knowledge, sixteen cases are reported in western literature. All the cases are associated with other diseases, cardiac malformations (12/17 patients; 16 plus the present case) and hepatic neoplasms being the most frequent observations. We present the case of a girl with a complex malformative syndrome consisting of multicystic kidney dysplasia, CAPV and nodular tumor-like mass of the liver. Angiography showed that the splenic vein and superior mesenteric vein joined to form a common trunk directly entering the inferior vena cava above the liver. A review of the CAPV cases of the literature and the clinical and pathological features of the hepatic lesion, classified as Focal Nodular Hyperplasia (FNH), are extensively discussed.