Pseudotumor cerebri. A theory on etiology and pathogenesis.

Ten patients with pseudotumor cerebri were studied. The diagnosis was based on bilateral papilledema and absence of intracranial masses and hydrocephalus. Based on the radiological findings, three groups of patients emerged: (A) Five patients with an empty sella. Four had an enlarged sella; (B) Two patients with a pituitary adenoma; and (C) Three patients without sellar or pituitary pathology. The onset of symptoms was acute in four patients, two from group A and one each from groups B and C. One patient from group A had a lesion of the chiasma. Two patients from group B and two from group C had symptoms and signs suggesting engagement of structures in the cavernous sinus. It is suggested that pseudotumor cerebri may be caused by bilateral compression of the cavernous sinuses because of acute necrotic swelling of a preexisting pituitary adenoma.