Diagnostic problems in nodular regenerative hyperplasia (nodular transformation) of the liver. Review of the literature and report of two cases.

Nodular regenerative hyperplasia (NRH) is a rare lesion of the liver associated with portal hypertension in more than half of patients. We present two cases demonstrating complications and diagnostic problems of NRH and review the pathogenesis, clinical, radiologic, and pathologic features of 240 cases in the literature. Patient 1 died from variceal bleeding as a complication of NRH. Patient 2 presented with ascites. Sonographic, computed-tomographic and magnetic resonance findings did not differ from liver cirrhosis. Three needle biopsies showed nonspecific reactive hepatitis. Wedge liver biopsy provided the correct diagnosis of NRH and a shunt operation was performed. Non-Hodgkin's lymphoma (centroblastic type) was diagnosed three years after NRH. At present there is no clinical or radiologic evidence of progression of NRH in this patient. The diagnosis of NRH cannot be made without histologic examination. Correct diagnosis is difficult in percutaneous needle biopsy. Therefore, laparoscopically guided liver biopsy or wedge biopsy is often necessary for diagnosis. NRH should be included in the differential diagnosis of portal hypertension. Portal diversion can be considered.