Sphenoid Sinus Fungus Balls Presenting with Skull Base Erosion and Associated Complications: A Case Series

Objective: To describe our institution's experience with sphenoid sinus fungus balls, including those resulting in skull base erosion, orbital and intracranial complications.

Design: A retrospective case review was performed on patients that underwent surgery for sphenoid sinus fungus balls from 2006 to 2013.

Setting: An academic tertiary care sub-specialty hospital

Participants: All patients that underwent surgery by the authors for sphenoid sinus fungus balls from 2006 to 2013 were included.

Main Outcomes: Demographic information, presenting symptoms, radiologic findings, pathologic and microbiologic results, type of surgery performed, surgical findings, and complications of skull base erosion were extracted from the medical record.

Results: A total of 39 patients underwent endoscopic surgery for sphenoid fungus balls between 2006 and 2013. The average age was 59.8 years (range 27 to 97.1 years), with 77% women. Average follow up time was 18 months. The most common presenting symptom was headache (64%). Previous nasal surgery was noted in 47% of patients, including three patients (7.7%) that underwent previous trans-sphenoidal pituitary surgery. Skull base erosion was seen in 38.4% of patients, and 20% demonstrated mucocele formation. CT findings demonstrated hyperostosis of the bone surrounding the sphenoid sinus in 66.7% of patients and hyperdensity within the sinus in 66.7% of patients. Presenting complications were seen in 10% of all patients and in 26.7% of patients with skull base erosion – the most common being visual loss. Three patients (7.7%) underwent emergent surgery for their complication. There were no cases of spinal fluid leak despite skull base erosion. Aspergillus was seen on pathology in 100% of cases without evidence of tissue invasion. Only 17% of all fungal cultures were positive. Six patients (15%) required a total of seven revision surgeries. There was no significant difference between patients who underwent trans-nasal or trans-ethmoid sphenoidotomy in need for revision surgery (p = 1.0).

Discussion: Sphenoid sinus fungus balls, while uncommon, can result in skull base erosion and orbital and intracranial complications. Our series demonstrates the high incidence of skull base erosion associated with sphenoid fungus balls, and the surprisingly high incidence of complications resulting from skull base erosion. Fungus balls should be suspected in isolated sphenoid sinus disease, especially with radiologic evidence of hyperdensity and hyperostosis. Management of fungus balls is surgical, with a wide sphenoidotomy performed and evacuation of fungal debris. Anti-fungal medical therapy is not required.