Hepatic inflammatory pseudotumor: case report, review of the literature, and a proposal for morphologic classification.

Inflammatory pseudotumors (IPT) are uncommon mass lesions arising most typically in the lungs of young adults. These tumors are so named because of the difficulty in distinguishing them preoperatively from malignant lesions. IPT are characterized histologically by localized fibrous proliferations with infiltration by mononuclear leukocytes, particularly plasma cells. Seventeen previous cases of IPT involving the liver and biliary tree have been reported in children. In this location, IPT may lead to biliary obstruction, portal hypertension, cirrhosis and eventually hepatic failure. We describe the youngest patient ever reported with hepatic IPT (HIPT) and biliary obstruction, who was successfully managed with a left hepatic lobectomy and Kasai portoenterostomy. Based on all previous cases of HIPT in both adults and children (74 cases), we propose a morphologic classification of these lesions based on the presence of single versus multiple lesions, with individualized management. Type 1 lesions are large, solitary lesions, often with central necrosis, giving a characteristic radiographic appearance. Type 2 lesions are multiple smaller, solid nodules indistinguishable from metastatic malignancy.