Ependymoma with cartilaginous metaplasia might have more aggressive behavior: a case report and literature review.

Ependymoma with cartilaginous metaplasia with or without bone formation is exceedingly rare. Only eight cases have been reported in the literature. We report a case of ependymoma with cartilaginous and osseous metaplasia in a 5-year-old boy. Microscopically, the tumor was composed of neoplastic ependymal tissue and mature cartilage and bone. Immunohistochemically, glial fibrillary acidic protein and epithelial membrane antigen were positive for ependymoma cells but negative for cartilage and bone. Recurrence occurred after 15-month follow-up. The patient deteriorated rapidly and died after 1 month. Reviewing 8 reported cases and our latest case, we found that 3 cases of ependymoma with cartilaginous metaplasia were treated with radiotherapy. Six cases had recurrence from 6 months to 8 years and 2 cases died on the day of operation. These findings suggest that ependymoma with cartilaginous metaplasia might have more aggressive clinical behavior.