We presented 3 cases with myxoid liposarcoma treated with preoperative radiotherapy (30Gy) and local wide resection (wide margin in one case and marginal margin in two cases). All of them are alive and free of disease 8 months, 11 months, and 20 months after surgery, respectively. The clinical evaluation of tumor response for radiation therapy was performed with various imaging modalities. In one case, we found mild shrinkage of a mass on CT accompanied by no uptake on scan with Gallium 67 citrate. Another case had definite shrinkage of a mass on CT. In the remainder, was revealed mild shrinkage of a mass with its clearer margin on CT. In the histological assessment of these resected tumors, the former two cases, described in the clinical response for irradiation, showed complete tumor destruction of more than 95% with remarkable collagenization in tumor and thickened fibrous pseudocapsule. The latter showed moderate collagenization of tumor with thickened fibrous pseudocapsule. Preoperative radiation therapy for myxoid liposarcoma produced some better effects to secure safer surgical margin, but the more demonstrable decrease in size of a tumor may not so strongly be expected because of various degree of collagenization due to radiotherapy.
