Abscess of the sphenoid sinus after transsphenoidal surgery. A case of a bacterial abscess developing in the sphenoid sinus 2 weeks after transsphenoidal surgery is presented. Although abscesses within the sella turcica have been reported as rare complications of transsphenoidal surgery, this is the first reported case of the postoperative formation of an abscess of the sphenoid sinus. The patient sought treatment for severe headaches, nausea and vomiting, and marked temperature elevation. A computed tomographic scan demonstrated soft tissue and air within the sphenoid sinus. A regimen of stress doses of hydrocortisone and antibiotics was prescribed, and the patient underwent transsphenoidal drainage of the sphenoid sinus. The sella turcica was not involved. Anaerobic cultures were positive for Fusobacterium necrophorum. 