Rapid progression of rhabdoid components of a composite high-grade glioma and rhabdoid tumor in the occipital lobe of an adult.

We report a very unusual case of a composite high-grade glioma and rhabdoid tumor in an adult. A 22-year-old woman presented with scintillating scotoma due to a solid tumor with surrounding brain edema in the right occipital lobe. The tumor was grossly resected. Histological examinations showed that the tumor was mainly composed of INI1-positive high-grade glioma tissue containing an INI1-negative rhabdoid component. She received radiation therapy and chemotherapy. Three months after the surgery, she again complained of visual disturbances, and tumor recurrence within the resection cavity was noted. A second operation was performed. The findings of histological examinations of the surgical specimen obtained during the second surgery were completely different from those of the specimen obtained during the initial surgery. Only the rhabdoid component showed remarkable proliferation and did not express INI1. Diffuse dissemination along the craniospinal axis eventually progressed, and she died 5 months after the initial diagnosis. We suggest that the inactivation of the INI1 gene affects potent proliferation activity and resistance to both chemotherapy and radiation therapy.