A Case of Adult-Onset Atypical Teratoid/Rhabdoid Tumor With Extracranial Metastasis.

A 47-year-old woman visited a hospital with complaints of headache and epistaxis. A mass lesion was found in the sellar region, and the patient underwent partial removal via transsphenoidal surgery at the hospital. Pathological diagnosis revealed an atypical teratoid/rhabdoid tumor (AT/RT), and she was referred to our hospital for postoperative adjuvant therapy. Although chemotherapy with ifosfamide, carboplatin, and etoposide (ICE regimen) was administered, the residual tumor rapidly grew, and the patient presented with visual disturbance. Irradiation significantly reduced the tumor size. She was stable for 17 weeks; however, dissemination occurred in the left frontal lobe and lumbar spinal cord, and multiple metastases to the lungs occurred. The patient was treated with additional irradiation, oral temozolomide, intrathecal methotrexate, and intrathecal cytarabine; however, these treatments were ineffective. The patient died 34 weeks postoperatively. AT/RTs are rare malignant embryonal tumors that primarily occur in infants and children under three years of age. Due to its rarity, a standardized treatment has not been established. Adult-onset AT/RTs are extremely rare, with a limited number of reported cases. Extracranial metastases are also uncommon and have only been reported in a few cases. The accumulation of additional cases is necessary to establish a standardized treatment. Therefore, here, we report an adult case of extracranial metastasis to contribute to this effort.