Atypical teratoid/rhabdoid tumors (AT/RT) rarely occur in the cauda equina; thus, the clinical behavior and optimal treatment remain unclear. A 9-year-old boy presented with a rapidly progressing intradural extramedullary tumor at the L2–5 level, underwent tumor resection, and was diagnosed with AT/RT. His gait disturbance improved postoperatively, and he received adjuvant chemotherapy and radiotherapy. In 5 months of follow-up, recurrence was not observed. Although extremely rare, AT/RT should be included in the differential diagnosis, as it requires prompt therapeutic intervention. Safe resection with minimal functional impairment, followed by postoperative chemoradiation, can lead to tumor control and improve neurological function.

Successful use of anti-PD-1 antibody to treat multiple metastatic carcinomas in a patient with xeroderma pigmentosum: case report and literature reviewMai Itoyama1, Akihiro Ohara1, Kazuki Yokoyama1, Shun Yamamoto1, Ken Kato1, Taisuke Mori2, Hiroshi Igaki3, Eiji Nakano4,5, Naoya Yamazaki4, Kuniko Sunami6, Chikako Nishigori5,7, Yoshitaka Honma11. Department of Head and Neck, Esophageal Medical Oncology, National Cancer Center Hospital2. Department of Diagnostic Pathology, National Cancer Center Hospital3. Department of Radiation Oncology, National Cancer Center Hospital4. Department of Dermatologic Oncology, National Cancer Center Hospital5. Department of Dermatology, Kobe University Graduate School of Medicine6. Department of Laboratory Medicine, National Cancer Center Hospital7. Hyogo Blood Center, Japanese Red CrossContact (Mai Itoyama):Adress: 5-1-1 Tsukiji, Chuo-ku, Tokyo, JapanEmail: mitoyama@ncc.go.jp