Eosinophilic granuloma of the occipital bone presenting as intracranial venous hypertension.

Intracranial venous sinus thrombosis is an uncommon cause of pseudotumor cerebri. The diagnosis is often not confirmed on the rationale that treatment will not be altered. We report a case presenting a pseudotumor cerebri where the underlying pathology disclosed dural sinus thrombosis resulting from compression by an eosinophilic granuloma of the occipital bone. Routine CT of the head and Technetium-99m brain scan initially demonstrated neither tumor nor thrombosis. Plain skull x-rays subsequently revealed a lytic lesion of the occiput. When reinvestigated with CT using bone density windows the tumor was revealed. Excision of the tumor and a short course of cobalt therapy was curative. Special techniques in nuclear scanning, CT and MRI designed to improve the sensitivity for diagnosing venous sinus thrombosis are described. This case illustrates the importance of establishing a definitive diagnosis and shows the importance of pre-test consultation between clinicians and radiologists to ensure that specific investigative techniques are properly utilized.