[Two cases of radiation myositis probably induced by recall phenomenon].

Two cases of radiation myositis following gemcitabine-based chemotherapy for advanced non-small cell lung cancer are presented. In the two cases, myositis appeared 3 and 5.5 months after the completion of radiation therapy and 2 and 2.5 months after the beginning of chemotherapy, respectively. The affected areas, the upper back and right thigh, appeared as areas of increased signal intensity on T2-weighted MR imaging and were enhanced by the administration of Gd-DTPA in the skeletal muscles. These coincided with the previously irradiated area. Although radiation myositis is a rare complication, it is important to be careful of radiation recall induced by chemotherapeutic agents.