A 58-year-old woman suffered pain due to a stage-IV adenocarcinoma of the right upper-lung lobe with signs of growth into the right axilla. Palliative local radiotherapy directed at the primary tumour followed by combination chemotherapy with carboplatin-gemcitabin led to partial remission. During the fourth and last cycle of her three-months course of chemotherapy, the patient again complained of pain in the right half of the thorax; later, a local swelling of the pectoralis muscles was found. She was diagnosed with myositis as a delayed reaction to irradiation (radiation-recall phenomenon) based on the clinical symptoms (redness of the skin, pain and distinct swelling) but especially on the basis of a CT-scan. This revealed a clear swelling of the pectoralis muscles, even though the tumour was in remission. The possibility of myositis as a radiation-recall phenomenon should be borne in mind whenever a patient presents with skin changes or pain within a previous irradiation field during chemotherapy with, for example, gemcitabin.