Nodular regenerative hyperplasia associated to aplastic anemia: a case report and literature review.

INTRODUCTION: Nodular regenerative hyperplasia (NRH) is a rare condition is associated to immune, neoplastic, vascular disorders, and certain drugs and toxins. Portal hypertension is the main complication. AIM: To report the case of a woman with NRH and aplastic anemia, association not previously described. CASE: A 31- year-old hispanic female presented with pancitopenia and cholestasis. Bone marrow biopsy: aplastic anemia. Abdominal ultrasound revealed multiple liver nodules, without hepato-splenomegaly. No abnormalities were noted in hepatic vessels. Antimitochondrial (AMAs) were positive. Coagulation tests were normal. Liver biopsy: hepatocite nodules with central atrophy and sinusoidal dilatation in the absence of significant fibrosis. No arteritis, thrombosis or bile duct damage was found. DISCUSSION: Pathogenesis of NRH remains unclear. The most accepted theory was developed by Wanless 24 years ago, and reinforced in 1997. It states that alterations in hepatic blood flow (portal obliterative venopathy) originate a specific response, initially consisting of apoptosis secondary to acute ischemia, with ensuing parenchymal atrophy and surrounding areas of liver regeneration and chronic ischemia. The common pathologic mechanism of all the diseases associated with NRH involves liver blood-flow abnormalities secondary to microthromboses, vascular congestion, or vasculitis. In the current case we were unable to document evidence of liver flow abnormalities. Noteworthy, there are previous descriptions of the as- sociation of NRH with primary biliary cirrhosis, and this patient was AMA positive, but without bile duct damage in liver biopsy.
CONCLUSIONS: We cannot sustain Wanless' theory, and this is the first description of the association of NRH with aplastic anemia.