Inflammatory pseudotumor of the liver diagnosed by needle liver biopsy under ultrasonographic tomography guidance.

Inflammatory pseudotumor of the liver is a rare benign lesion, but exploratory laparotomy and a hepatectomy are often performed unnecessarily after various misdiagnoses, including liver abscess, hepatocellular carcinoma, metastatic liver tumor, and cholangiocarcinoma. We present a case of hepatic inflammatory pseudotumor in a 17-year-old man in whom diagnosis was confirmed by liver needle biopsy under ultrasonographic tomography (UST) guidance. He had complained of fever and right hypochondralgia 2 months after being operated for appendicitis. He was admitted to our hospital because of the persistence of these symptoms and the presence of a hepatic mass lesion detected by UST. He had hepatomegaly, with tenderness; leukocytosis and elevated erythrocyte sedimentation rate and C-reactive protein level were noted. UST showed a hypoechoic mass in the liver and pre-contrast computerized tomography (CT) revealed a low-density area with an ill defined margin, which was barely enhanced by the contrast medium. On the basis of the patient's clinical symptoms and the laboratory data and imaging studies, the presence of a liver abscess was suspected and antibiotics were administered. One month after the initiation of the antibiotic therapy, UST demonstrated that the portal vein had dilated serpiginously and penetrated into the mass. As the heterogeneous appearance displayed by post-enhanced CT indicated the need for a differential diagnosis of the hepatic mass lesion to rule out hepatocellular carcinoma, percutaneous needle biopsy was performed, under UST guidance. Histopathological examination demonstrated marked infiltration of plasma cells and fibrosis, findings which were consistent with those of hepatic inflammatory pseudotumor. There was a spontaneous reduction of the hepatic pseudotumor without continuous antibiotics and this reduction was documented on follow-up UST and CT.