To report a patient with suspected idiopathic intracranial hypertension (IIH) ultimately diagnosed with dural arteriovenous fistula (DAVF) and PTEN mutation.

Clinical Course:

A 31-year-old woman presented with headache, pulsatile tinnitus, postural tunnel vision, and papilledema. Brain MRI and MR Venography (MRV) were normal. Lumbar puncture revealed opening pressure of 36 cm H2O with normal cerebrospinal fluid. She was diagnosed with IIH and started on acetazolamide 3,000 mg daily. Optic disc swelling improved but did not resolve. VF worsening often accompanied dose reductions. At age 33, she underwent nephrectomy for clear cell renal carcinoma. She lost 40 pounds; however IIH symptoms persisted. Repeat imaging showed distal transverse sinus stenosis.  At age 38, she remained acetazolamide-dependent and had a progressive visual field deficit in the left eye. Repeat MRI and MRV raised concern for a DAVF, confirmed by conventional angiography, that was embolized with reduction in intracranial pressure. Within two weeks, symptoms and signs of increased intracranial pressure improved. Genetic workup given personal and family histories of malignancy was positive for the PTEN+ p. R130* mutation. She was ultimately diagnosed with the PTEN Hamartoma Syndrome.

Persistent dependence on high doses of acetazolamide for years in a patient with presumed IIH should lead to constant re-evaluation of the underlying cause for raised intracranial pressure. The presence of malignancy and a DAVF may suggest a PTEN mutation.