INFLAMMATORY MYOFIBROBLASTIC TUMOR (INFLAMMATORY PSEUDOTUMOR) - DNA FLOW CYTOMETRIC ANALYSIS OF 9 PEDIATRIC CASES

BACKGROUND, Inflammatory myofibroblastic tumor or inflammatory pseudot umor is an uncommon lesion reported in various organs and believed to be a nonneoplastic reactive inflammatory condition. The concept of ben ign lesion has been recently challenged from both clinical demonstrati on of recurrence and cytogenetic evidence of acquired clonal chromosom al abnormality. Because DNA aneuploidy can be a useful marker for neop lasia, we analyzed nuclear DNA content of these lesions using flow cyt ometry. METHODS, In this study, inflammatory myofibroblastic tumors fr om nine children were examined retrospectively by evaluating clinicopa thologic features and ploidy. DNA ploidy status was analyzed by flow c ytometry in nuclei isolated from paraffin-embedded tumor tissues. RESU LTS, Three of the nine patients had local recurrence or distant metast ases. Flow cytometric DNA analysis revealed five of the nine cases wer e diploid and four hyperdiploid (DNA indices 1.14, 1.16, 1.19, and 1.3 3). All lesions had a low S-phase fraction. Samples from the three sub jects with clinical recurrence were all hyperdiploid. CONCLUSIONS, The present data indicate that flow cytometry identifies aneuploidy (hype rdiploidy) in approximately half of the cases of inflammatory myofibro blastic tumors. This feature appears to reflect a more aggressive biol ogic behavior. In addition to the reported cytogenetic abnormalities, our data suggest that inflammatory myofibroblastic tumor, generally co nsidered a benign reactive inflammatory process, may evolve as a disti nct, potentially malignant, lesion. Therefore, flow cytometric DNA ana lysis is a suitable tool to provide the clinician with both diagnostic and prognostic information and to individuate the most feasible thera peutic approach. (C) 1996 American Cancer Society.