A case of idiopathic portal hypertension associated with nodular regenerative hyperplasia-like nodule of the liver and mixed connective tissue disease.

A 51-year-old woman was diagnosed with mixed connective tissue disease (MCTD) in 2011. She underwent treatment with prednisolone. Her hepatobiliary enzyme level increased, and multiple nodules were found in both liver lobes in abdominal imaging studies. Ultrasonography revealed large and small hyperechoic lesions with indistinct or well-defined borders. No findings of classic hepatocellular carcinoma or liver cirrhosis were observed on contrast-enhanced computed tomography, but some nodules showed an enhanced effect of the central lesion that was characteristic of focal nodular hyperplasia (FNH) in an arterial phase. On gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, slightly high-intensity nodules, 10-40mm in size, were observed on T1- and T2-weighted images. The nodules showed highest intensities in the hepatocyte phase and were enhanced with the uptake of Gd-EOB-DTPA as compared with the background liver. FNH was suspected based on the imaging findings, but we performed a liver tumor biopsy for differential diagnosis of the malignant lesion. Based on the immunohistopathological examination results, the final diagnosis was idiopathic portal hypertension associated with nodular regenerative hyperplasia (NRH)-like nodule of the liver. Benign nodular hepatocellular lesions are caused by abnormal hepatic circulation and were previously known as anomalous portal tract syndrome. Our case of atypical NRH with large nodules may be included in this disease entity. Here, we report a rare case of MCTD with NRH-like nodules and idiopathic portal hypertension with a review of literature.