Intraparenchymal chordoid meningioma: a case report and review of the literature.

Most meningiomas are benign and correspond to World Health Organization grade I, whereas chordoid meningioma is a rare subtype, which is regarded as grade II. This report presents 1 case of intraparenchymal chordoid meningioma. The intraparenchymal chordoid meningioma consisted predominantly of tissue that was histologically similar to chordoma, featuring cords or trabeculae of eosinophilic and often vacuolated cells in an abundant mucoid matrix background. Tumor cells were diffusing positive for epithelial membrane antigen and vimentin, and focusing positively for progesterone receptor, but showed lack of immunoreactivity with cytokeratin, S-100, and glial fibrillary acidic protein. Follow-up at 8 months showed no recurrence. Reports about chordoid meningioma are not uncommon, but reports on intraparenchymal lesion are rare. Besides, the result of magnetic resonance imaging in the present case suggested that intraparenchymal chordoid meningioma was a metastasis tumor. This report reminds of the importance of differential diagnosis in the case of intraparenchymal lesion.