Pituitary abscess following endoscopic endonasal drainage of a suprasellar arachnoid cyst: Case report and review of the literature.

Arachnoid cysts are uncommon lesions of the sellar region, and only rarely require decompressive surgery to treat symptoms. Pituitary abscesses are another rare lesion, and are an uncommon complication of pituitary surgery. A previously healthy 45 year old woman presented with a new finding of bitemporal hemianopsia. Magnetic resonance imaging (MRI) showed a cystic sellar lesion with suprasellar extension and compression of the optic chiasm. Endoscopic transphenoidal surgery was performed and the lesion was found to be an arachnoid cyst. She was well immediately after the operation, but 1 week later presented with headaches, fever and worsening visual acuity. MRI showed a homogenous collection in the sellar region that was compressing the chiasm. The patient was treated with antibiotics, and a second transphenoidal operation was performed, with frank pus found in the pituitary fossa. Cultures of the fluid found during the operation grew Escherichia coli and Staphylococcus lugdunensis. Her symptoms resolved after the second operation, and formal visual fields and a pituitary hormone panel were normal at this time. We report on a rare case of a pituitary abscess complicating surgery for a sellar arachnoid cyst, and discuss management of these conditions.