Soft-tissue sarcomas: MR imaging findings after treatment in three pediatric patients.

PURPOSE

To characterize the skeletal and bone marrow magnetic resonance (MR) imaging changes during and after treatment of childhood soft-tissue tumors.

MATERIALS AND METHODS

Three boys with soft-tissue sarcomas of the popliteal fossa underwent surgery, radiation therapy, and chemotherapy. Plain radiographic and MR imaging findings were correlated with the effect of treatment.

RESULTS

After radiation therapy, MR images revealed findings that resembled those of rickets at sites of irradiation in the three patients. These findings included metaphyseal sclerosis, metaphyseal fraying, and epiphyseal plate widening. Bone marrow imaging changes were temporally related to therapy. During chemotherapy, reconversion to hematopoietic marrow was noted in nonirradiated areas in two patients, but after cessation of all treatment, these areas converted back to fatty marrow. Irradiated areas of bone marrow remained fatty throughout therapy in the three patients.

CONCLUSION

Awareness of the MR imaging findings related to antineoplastic treatment of soft-tissue tumors is important to distinguish these changes from progression of primary disease.