The development of numerous radiation-induced cavernous malformations in a germ cell tumor patient: A case report.

Radiation-induced cavernous malformations (RICMs) are most commonly reported in young patients who have previously received radiotherapy. Here, we report a case of a patient with a germ cell tumor who was treated with whole brain radiotherapy (WBRT) and then incidentally found to have numerous RICMs. A 31-year-old male visited the hospital for a testicular mass. On examination, he was diagnosed with a mixed germ cell tumor with lung/brain metastases. The patient underwent a left orchiectomy and received 4 cycles of chemotherapy. He was then treated with WBRT for residual lesions in the brain and a wedge resection for the lung metastasis. Four years later, approximately 250-300 RICMs were incidentally observed in a follow-up brain image. Because the patient had not noticed any symptoms and the RICMs were small in size, he was not treated. To our knowledge, this is the first reported case of numerous (approximately 250-300) RICMs in a germ cell tumor patient after WBRT. Herein, we report details of this case and discuss the typical clinical features of RICM.