Inflammatory myofibroblastic tumor (inflammatory pseudotumor): DNA flow cytometric analysis of nine pediatric cases.
BACKGROUND
Inflammatory myofibroblastic tumor or inflammatory pseudotumor is an uncommon lesion reported in various organs and believed to be a non-neoplastic reactive inflammatory condition. The concept of benign lesion has been recently challenged from both clinical demonstration of recurrence and cytogenetic evidence of acquired clonal chromosomal abnormality. Because DNA aneuploidy can be a useful marker for neoplasia, we analyzed nuclear DNA content of these lesions using flow cytometry.


METHODS
In this study, inflammatory myofibroblastic tumors from nine children were examined retrospectively by evaluating clinicopathologic features and ploidy. DNA ploidy status was analyzed by flow cytometry in nuclei isolated from paraffin-embedded tumor tissues.


RESULTS
Three of the nine patients had local recurrence or distant metastases. Flow cytometric DNA analysis revealed five of the nine cases were diploid and four hyperdiploid (DNA indices 1.14, 1.16, 1.19, and 1.33). All lesions had a low S-phase fraction. Samples from the three subjects with clinical recurrence were all hyperdiploid.


CONCLUSIONS
The present data indicate that flow cytometry identifies aneuploidy (hyperdiploidy) in approximately half of the cases of inflammatory myofibroblastic tumors. This feature appears to reflect a more aggressive biologic behavior. In addition to the reported cytogenetic abnormalities, our data suggest that inflammatory myofibroblastic tumor, generally considered a benign reactive inflammatory process, may evolve as a distinct, potentially malignant, lesion. Therefore, flow cytometric DNA analysis is a suitable tool to provide the clinician with both diagnostic and prognostic information and to individuate the most feasible therapeutic approach.
Biselli
R
R
Italian Air Force, DASRS, Aerospace Medical Department, Pratica di Mare, Rome, Italy.
Ferlini
C
C
Fattorossi
A
A
Boldrini
R
R
Bosman
C
C
D002648:Child; D002675:Child, Preschool; D003108:Colonic Diseases / Q000473:pathology; D004247:DNA / Q000032:analysis*; D018870:Endoplasmic Reticulum, Rough / Q000473:pathology / Q000648:ultrastructure; D004822:Epididymis; D005260:Female; D005434:Flow Cytometry; D006104:Granuloma, Plasma Cell / Q000235:genetics* / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008171:Lung Diseases / Q000473:pathology; D008297:Male; D016727:Orbital Pseudotumor / Q000473:pathology; D012008:Recurrence; D012189:Retrospective Studies; D013733:Testicular Diseases / Q000473:pathology
D004247:DNA