Patterns of dural involvement in sinonasal tumors: prospective correlation of magnetic resonance imaging and histopathologic findings.

BACKGROUND

The presence of dural invasion serves as an important negative predictive factor for survival in sinonasal and skull-base neoplasms. The objective of this study was to prospectively correlate preoperative magnetic resonance imaging (MRI) findings with intraoperative surgical findings and histopathology to establish key correlates for dural involvement in sinonasal tumors.

METHODS

Prospective blinded MRI review of 50 sinonasal and anterior skull-base neoplasms was performed by a staff neuroradiologist. Retrospective chart review was performed to accrue salient patient and tumor data.

RESULTS

The mean patient age was 54.6 years with a male:female ratio of 1.8:1. The most common tumor histology included adenocarcinoma (18%), squamous cell carcinoma (18%), mucosal melanoma (8%), and olfactory neuroblastoma (8%). MRI demonstrated dural enhancement in 20 patients (40%), with 1 mm and ≥2 mm thickening being noted in 14 (70%) and 6 (30%) cases, respectively. Spectrum of MR findings in these 20 patients included linear enhancement in 15 (75%), nodular thickening in 5 (25%), and loss of hypointense zone in 13 (65%) cases. Intraoperative findings and histology confirmed dural invasion in 12 of 20 cases (60%). Positive predictive value (PPV) of linear and nodular dural enhancement for dural invasion was 46.7% and 100%, respectively. One millimeter (1 mm) and ≥2 mm of dural thickening demonstrated PPV of 42.9% and 100%, respectively. Loss of the hypointense zone had PPV of 92.3% for dural invasion. Fisher's exact test demonstrated that loss of hypointense zone and dural thickening ≥2 mm were statistically associated with dural involvement (p < 0.05).

CONCLUSION

The presence of ≥2 mm of dural thickening, loss of hypointense zone, and nodular dural enhancement were highly predictive for presence of dural invasion by sinonasal malignant tumors. Preoperative knowledge of these MRI patterns may better guide surgical planning and patient counseling.