A Case of Radiation Recall Myositis Induced by 5-FU and Cisplatin

ABSTRACT

Radiation recall phenomenon is an inflammatory reaction which occurs at a previously irradiated area after the administration of causative agents, especially anticancer drugs. Radiation recall mostly involves skin and rarely affects internal organs. We, hereby, report a rare case of radiation recall myositis. A 51-years-old man visited the hospital due to pain and weakness of the left thigh. He had been diagnosed with a skin metastasis of pancreatic adenocarcinoma, at the left thigh and treated with radiotherapy and subsequent combination chemotherapy of 5-FU and cisplatin. After the 5th cycle of chemotherapy, the patient developed pain and weakness localized at the previous radiation field. An MRI revealed myositis of left gluteus medius muscle. Muscle biopsy showed no malignant cells or signs of infection. He was diagnosed as having radiation recall myositis and treated with steroid and NSAID. Soon after, pain and weakness gradually improved. Although rare, a possibility of radiation recall myositis should be considered when a patient with history of radiotherapy has a myopathy.