Significance of nodular regenerative hyperplasia occurring de novo following liver transplantation.

Nodular regenerative hyperplasia (NRH) of the liver usually occurs in patients with rheumatological and myelolymphoproliferative disorders; the occurrence post-liver transplantation (LT) has traditionally been ascribed to the use of azathioprine. We report the clinical, biochemical, and radiological features of 14 patients who developed NRH, unrelated to azathioprine in most cases, 3 months to 11 yr after orthotopic LT. A total of 10 patients developed NRH within 4 yr (early onset), and 4 other patients developed the condition beyond 4 yr of LT (late onset). A total of 7 symptomatic patients, all in the early group, had features of portal hypertension with vascular abnormalities on Doppler ultrasonography that were preceded by the diagnosis of NRH. All asymptomatic patients, including each of the 4 patients in the late group, had normal hepatic ultrasound (US) studies. Two symptomatic patients had normalization of histologic abnormalities after correction of vascular abnormalities. In conclusion, observation is appropriate for patients who develop NRH late following LT. Patients in whom NRH is detected on liver biopsy early after transplantation are likely to develop portal hypertension in the future. Intervention aimed at correcting the vascular abnormalities in these patients may result in clinical as well as hepatic histological improvement. (c) 2007 AASLD.