A primary extradural malignant rhabdoid tumor at the craniovertebral junction in a 3-year-old boy

Takuma Nishimoto, Sadahiro Nomura, Reiji Fukano, Tokuhiro Kimura, Eiji Ikeda, Michiyasu Suzuki

Malignant rhabdoid tumor (MRT) is a highly aggressive childhood neoplasm and mainly presents in kidney and brain. We report the case of a patient with extrarenal extracranial MRT in the craniovertebral junction (CVJ). A 3-year-old boy presented with tetraparesis that had rapidly developed for 2 weeks. The tumor was located in the ventral side of the C1 and C2 extradural space and had invaded the lower clivus. The symptom recovered after subtotal resection of the tumor through a lateral approach with removal of bilateral lateral masses at C1 and instrumental occipital-C2 posterior fusion. Definite histological diagnosis of the extradural tumor was difficult; however, a metastatic lesion in the rib showed a proliferation of INI1/SMARCB1-negative spindle and rhabdoid cells, indicating the tumor was MRT. Stereotactic CyberKnife radiotherapy with a marginal dose of 26 Gy contributed to control of local regrowth of the tumor before histopathological confirmation and induction of chemotherapy with ifosfamide, cisplatin, and etoposide. The patient survived for 29 months without local recurrence of the tumor and with independent activity, however then died of multiple metastases. Treatment strategies for MRT in the CVJ should include an optimal surgical approach for reduction of tumor volume and stabilization of the spine, followed by high dose chemotherapy. Stereotactic radiotherapy may be useful for local control.