Vascular invasion by hepatic inflammatory pseudotumor. A clinicopathologic study.

BACKGROUND: Unusual lesions composed of fibrous tissue, lymphocytes, histiocytes, and plasma cells, called inflammatory pseudotumors (IPT), are being increasingly recognized in many organs and tissues. A hepatic IPT extending into the inferior vena cava has never been reported before to the authors' knowledge. The patient in this study underwent liver resection with cardiopulmonary bypass and circulatory arrest to excise the IPT.
METHODS: The tissue was studied extensively using histologic, immunohistologic, flow cytometric, and gene rearrangement analysis and electron microscopic methods.
RESULTS: On gross examination, the large hepatic tumor resembled a malignancy invading the vena cava. Microscopically, 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 immunoglobulin and T-cell receptor genes did not detect evidence of clonal expansion of B-cells or T-lymphocytes.
CONCLUSIONS: This experience with the vascular invasive and biliary obstructive nature of IPT and the difficulty in diagnosing it before or during surgery underscores the potentially adverse impact of this lesion on patients. The authors believe that an aggressive approach should be taken when evaluating and treating hepatic masses, even though they may later be confirmed as being IPT.