Nodular Regenerative Hyperplasia after Liver Transplantation Complicated with Inferior Vena Cava Stenosis: a Clue for Etiopathogenesis?

Nodular regenerative hyperplasia is a histopathological diagnosis characterized by the diffuse transformation of the liver parenchyma into regenerative nodules associated with rheumatologic and hematologic disorders, azathioprine immunosuppression or vascular injuries. The authors report the case of a 60-year-old female patient with a diagnosis of familial systemic paramyloidosis submitted to liver transplantation complicated by a hepatic artery thrombosis. A second liver transplant was performed and after 6 months she developed ascites and peripheral edema. The abdominal computed tomography (CT) showed an inferior vena cava stenosis. She underwent balloon angioplasty and an endovascular prosthesis was placed. The patient remained asymptomatic under immunosuppression with tacrolymus for 4 years, when she complained of peripheral edema and ascites. Laboratory work-up showed anemia and hypoalbuminemia with liver chemistry within the normal range. The ascites fluid analysis revealed a serum ascites albumin gradient superior to 1.1 g/L. Abdominal Doppler ultrasound and abdominopelvic CT angiogram confirmed endovascular prosthesis permeability. A percutaneous hepatic biopsy specimen was taken and histologic analysis showed, with reticulin stain, focal regenerative nodules of hyperplastic hepatocytes and internodular hepatocyte atrophy, compatible with the diagnosis of nodular regenerative hyperplasia. The case described is of particular interest as the nodular regenerative hyperplasia occurred after liver transplantation complicated with inferior vena cava stenosis, which might have contributed in a crucial way to liver parenchyma transformation.