fig 1.

Case 1. A, Axial unenhanced CT scan shows a soft-tissue density mass in the sphenoid sinus. The mass is seen to expand the sinus.

B, Sagittal T1-weighted MR image (600/16/1 [TR/TE/excitations]) shows the nasopharyngeal component of the sphenoid mass. Note that the floor of the sella appears intact.

C, Coronal contrast-enhanced T1-weighted MR image (433/17/1) shows mild heterogeneous enhancement of the sphenoid sinus mass.

D, Axial fast spin-echo T2-weighted MR image (3250/95/3) shows the sphenoid sinus mass to be heterogeneously hyperintense.

E, Neuroendocrine carcinoma of the sphenoid sinus consisting of small pleomorphic cells exhibiting crowded hyperchromatic nuclei (hematoxylin and eosin stain; original magnification, ×40).