First case report of radiation-recall myositis following trabectedin in patient with stage IV mesenchymal chondrosarcoma.

Radiation recall is a rare phenomenon in which inflammation ensues on a previously irradiated tissue after the administration of a precipitating systemic agent. This reaction may appear anytime between weeks to years after radiotherapy, and it can be caused by a variety of drugs (mainly cytotoxic agents). Skin is the most commonly involved organ and despite the poor insight regarding the pathophysiology of this phenomenon, many case reports have been published on radiation recall dermatitis. In one third of cases, however, radiation recall occurs within internal organs or subcutaneous tissues. Radiation recall myositis is a rare example of this, which has most frequently been reported after the administration of gemcitabine in oncologic patients. We report a case of trabectedin-induced radiation recall myositis occurring 5months after stereotactic body radiation therapy on a metastatic muscle lesion in a patient with stage IV mesenchymal chondrosarcoma. To our knowledge, this is the first published case of trabectedin-induced radiation recall myositis.