Benign fibrous histiocytoma of the skull with increased intracranial pressure caused by cerebral venous sinus occlusion.

The authors present a very rare case of benign fibrous histiocytoma of the skull with increased intracranial pressure caused by sinus occlusion. A 33-year-old woman was referred for investigation of a right occipital protrusion with tenderness and double vision. She had only mild divergence insufficiency and bilateral papilledema neurologically. Imaging findings showed that the skull tumor was located at the right occipital bone with bone disruption and a compressed right sigmoid sinus. When planning the resection, caution was required to spare the collateral flow so as to manage the intracranial pressure. Immunohistochemical analysis showed that the tumor was positive for CD68, alpha1-antichymotrypsin, and alpha1-antitrypsin. From these findings, the tumor was diagnosed as a primary benign fibrous histiocytoma of the skull.