SOFT-TISSUE SIGNAL ABNORMALITY ASSOCIATED WITH EOSINOPHILIC GRANULOMA- CORRELATION OF MR-IMAGING WITH PATHOLOGICAL FINDINGS

Six patients with eosinophilic granuloma were studied retrospectively in order to correlate the MRI appearances with the pathology. Ages ran ged from 2 years 6 months to 11 years. The bones involved were the hum erus, ulna, radius, femur, clavicle and ilium. Plain films, MRI and pa thology specimens were obtained. A lytic lesion with indistinct margin s, endosteal erosions and periosteal reaction was seen in all cases on plain radiographs. Bone marrow signal was decreased on T1-weighted im ages and increased on T2-weighted images throughout the bony lesion in all cases. T2-weighted images showed extensive soft-tissue abnormalit ies suggesting inflammatory changes in four cases. In two cases abnorm alities were limited. Extensive changes correlated histologically with an early phase lesion. Localized minor changes were associated with a mid-phase lesion. Inflammatory soft-tissue changes could be associate d with eosinophilic granuloma. The size of the soft tissue mass correl ated well with the activity of the bony lesion.