Aneurysmal Bone Cysts of the Paranasal Sinuses: The Mayo Clinic Experience and Review of the Literature

Background/Purpose: Aneurysmal bone cysts (ABCs) are benign, lytic bone lesions that commonly arise in long bones and vertebral column, and more rarely in the head and neck. Presentation in the paranasal sinuses is an even rarer entity and there is no consensus in the literature on the appropriate diagnostic or treatment approaches for these patients. The purpose of this study was to elucidate the clinical behavior, treatment, and outcomes for patients presenting with ABCs of the paranasal sinuses.

Methods: A literature search was performed to identify reports of ABCs of the paranasal sinuses (psABC) in the literature. Additionally, a retrospective chart review was performed to identify patients evaluated at the authors’ center with a histopathologically confirmed diagnosis of psABC.

Results: A total of 90 patients (82 cases from the literature search and 8 cases from the author’s institution) met inclusion criteria. The median age at diagnosis was 14 years (range, 4 months–90 years) and median symptom duration prior to presentation was 4 months (range, 3 days–6 years). The most common presenting symptom was painless facial swelling (n = 35, 38.9%). The ethmoid sinuses were the most likely subsite involved (n = 55, 61.1%) followed by unilateral maxillary sinus involvement (n = 24, 26.7%). Also, 86 patients (95.6%) underwent surgical treatment. The surgical approach was reported in 75 cases, with 20 cases (26.7%) done completely endoscopically and 55 (73.3%) requiring an open or combined approach. Further, 61 patients (70.9%) underwent an R0 resection of their tumor, 23 patients (26.7%) underwent an R1 resection, and 2 patients did not have any data reported for the amount of tumor resected. 10 patients (11.1%) underwent adjuvant radiation therapy. Follow-up data were reported for 68 patients. Median follow-up time was 14 months (range, 1 month–10 years). But 16 patients (23.5%) were found to have a poor outcome (recurrence or progression of their disease) at follow-up. Only 11 of these patients (68.8%) had recurrence or progression within the first 12 months after treatment. Based on univariate Cox’s proportional hazard models, patients were more likely to have a poor outcome if they presented with proptosis (HR = 3.73) or orbital involvement on imaging (HR = 3.22). Factors that did not have a statistically significant effect on outcome included age at diagnosis, sex, medical comorbidity, diagnosis of fibrous dysplasia, adjuvant treatment with radiation or medical therapy, or presence of bilateral or multisinus disease ([Fig. 1]).

Conclusion: psABCs typically present with symptoms of painless swelling or nasal obstruction. Orbital involvement at the time of presentation is a negative prognostic indicator with these patients being more likely to have recurrence after treatment. Recurrence or progression of disease is most likely to occur in the first year after treatment and therefore patients should be monitored closely during this time period.

Fig. 1 Kaplan–Meier estimate of time to event (recurrence or progression).