Detection of Epstein-Barr Virus in inflammatory pseudotumor.

Inflammatory pseudotumors appear to represent a heterogeneous group of diseases that share common histopathologic features. A subset of these tumors, particularly those in the spleen and liver, harbor the Epstein-Barr virus (EBV) in spindled cells. Methods for detecting EBV in these tumors and the reliability of the different detection methods are discussed. Some EBV-positive inflammatory pseudotumors contain an increase in EBV-positive follicular dendritic cells and demonstrate monoclonal EBV genomes. At least one such case has recurred locally as an unusual EBV-positive follicular dendritic cell tumor. These rare reports support the concept of a distinct EBV-positive, follicular dendritic cell type of inflammatory pseudotumor that may be at increased risk for local recurrence. Many more cases of this rare type of inflammatory pseudotumor must be studied and reported before the clinical validity of such a distinction can be proven. Although EBV detection in spindled cells is unusual, it has been demonstrated in rare smooth muscle tumors arising in immunosuppressed children and young adults.