Magnetic resonance images before surgery. (A) T1-weighted PNS MRI showed a primary lesion of slightly lower signal intensity in the left nasal cavity. (B) The lesion was heterogeneously isointense on T2-weighted images. (C) Contrast-enhanced MRI showed heterogeneous enhancement of the lesion. (D) Coronal reconstruction of a T1-weighted MRI scan revealed an isolated primary lesion with no evidence of direct attachment to brain tissue.