Malignant solitary fibrous tumor arising from the pineal region: case study and literature review.

We report a case of malignant solitary fibrous tumor involving the pineal region in a 49-year-old woman. The patient presented with headache, slowly progressive weakness of the right lower extremities and upgaze palsy over the past year. Histologically, the tumor was composed of moderately hypercellular proliferated spindle cells with eosinophilic collagen bands. These cells were diffusely and strongly immunoreactive with CD34, CD99, and vimentin, but were negative with epithelial membrane antigen, S-100 protein, Bcl-2, smooth muscle actin, cytokeratin and glial fibrillary antigenic protein. MIB-1 labeling indices and mitosis rates were 7.3 +/- 1.8% and 5 per 10 high power fields, respectively. Ultrastructural examination revealed that the neoplastic cells had features of fibroblastic differentiation. Differential diagnoses included fibrous meningioma and hemangiopericytoma. The present case provides one unique example of a rare entity to the already diverse spectrum of the pineal region neoplasms encountered in neuropathology.