Imaging Characteristics and Clinical Outcomes of Biphenotypic Sinonasal Sarcoma

Introduction: Biphenotypic sinonasal sarcoma is a new and rare tumor characterized by concomitant neural and myogenic differentiation. This study describes the imaging characteristics and clinical outcomes of this sinonasal malignancy.

Methods: A retrospective review of all patients with biphenotypic sarcoma treated within the Mayo Clinic System between 2009 and 2017 was performed. CT/MRI characteristics and clinical outcomes were reviewed and are described.

Results: Five patients underwent surgical resection of biphenotypic sinonasal sarcoma. The median age was 56 years (range: 44–69) and 80% (n = 4) were female. Negative margins were achieved in all patients and there were no deaths noted within the review period. Two (40%) patients developed recurrences with median time to recurrence of 20.9 months. Review of imaging characteristics revealed a median tumor size of 3.8cm (range: 2.7–6.4 cm) in greatest dimension. In all cases, the tumors were unilateral and the epicenters involved the nasal cavity and ethmoid sinuses. There was a variable degree of involvement of the adjacent sinuses. In all cases, the tumors extended to the nasal septum, lamina papyracea, and anterior skull base with variable degrees of erosion through these structures. Hyperostotic bone was identified in 80% (n = 4) of cases. On MRI, the tumors were isointense-to- mixed iso/hypointense on T1-weighted signal and mixed iso/hyperintense-to-hypointense on T2-weighted signal (compared with gray matter). All cases demonstrated tumor enhancement and in 75% of cases, this enhancement was heterogenous.

Conclusion: Biphenotypic sinonasal sarcoma is a locally aggressive tumor. The imaging characteristics and surgical outcomes of this cohort are characterized.

No conflict of interest has been declared by the author(s).