Paranasal sinus and skull base fibro-osseous lesions: when is biopsy indicated for diagnosis?

Paranasal sinus fibro-osseous (FO) lesions represent a heterogeneous group, often sharing overlapping radiographic and pathologic features posing a dilemma in accurate diagnosis. The objective of this study was to correlate preoperative radiologic and postoperative histologic diagnosis to help guide a diagnostic algorithm.

Retrospective analysis of 60 FO lesions between 1994 and 2010.

The mean age was 42.3 years with average follow-up of 12.5 months. The preliminary radiologic diagnosis was osteoma in 22 (36.7%), fibrous dysplasia (FD) in 9 (15%), ossifying fibroma (OF) vs FD in 5 (8.3%), and OF in 3 (5%) cases. The diagnosis was indeterminate in 21 (35%) cases. Management consisted of excision in 29 (48.3%), observation in 17 (28.3%), and biopsy in 14 (23.3%) patients. For patients undergoing resection or biopsy, positive predictive value of preoperative radiology was 100% (10/10) for osteoma, 85.7% (6/7) for FD, and 33.3% (1/3) for OF cases. For the indeterminate lesions, most common pathologic diagnoses for 21 patients included osteoma in 4 (17.4%), arrested pneumatization in 3 (14.3%), OF in 3 (14.3%), and FD in 2 (9.5%). For FD vs OF cases, 3 underwent surgery, revealing osteoma, FD, and OF in 1 patient each.

In this series, radiologic-histopathologic correlation was high for osteoma and FD and low for OF and OF vs FD. This data suggests that patients with classic radiologic characteristics of osteoma and FD may be observed, unless resection is warranted based on clinical symptomatology. Preoperative diagnosis of OF, OF vs FD, or indeterminate lesions may warrant a biopsy to establish firm diagnosis to guide definitive management, especially if preoperative computed tomography (CT) imaging is concerning for an aggressive FO neoplasm.