VASCULAR INVASION BY HEPATIC INFLAMMATORY PSEUDOTUMOR - A CLINICOPATHOLOGICAL STUDY

Background. Unusual lesions composed of fibrous tissue, lymphocytes, h istiocytes, and plasma cells, called inflammatory pseudotumors (IPT), are being increasingly recognized in many organs and tissues. A hepati c IPT extending into the inferior vena cava has never been reported be fore to the authors' knowledge. The patient in this study underwent li ver resection with cardiopulmonary bypass and circulatory arrest to ex cise the IPT. Methods. The tissue was studied extensively using histol ogic, immunohistologic, flow cytometric, and gene rearrangement analys is and electron microscopic methods. Results. On gross examination, th e large hepatic tumor resembled a malignancy invading the vena cava. M icroscopically, a mixture of T-lymphocytes, B-lymphocytes, and plasma cells were scattered throughout the tumor. DNA flow cytometry did not reveal aneuploidy suggestive of neoplasia. Genetic analysis of the imm unoglobulin and T-cell receptor genes did not detect evidence of clona l expansion of B-cells or T-lymphocytes. Conclusions. This experience with the vascular invasive and biliary obstructive nature of IPT and t he difficulty in diagnosing it before or during surgery underscores th e potentially adverse impact of this lesion on patients. The authors b elieve that an aggressive approach should be taken when evaluating and treating hepatic masses, even though they may later be confirmed as b eing IPT.