An antrochoanal polyp is seen arising from the left maxillary sinus extending through a widened, smoothly remodelled meatus to fill the whole ipsilateral nasal cavity and the nasopharynx.
The polyp is homogenous T2 hyperintense and T1 isointense with smooth peripheral enhancement on T1C+.
The remainder ipsilateral sinuses are opacified by retentional phenomenon. There is no restricted diffusion.
A small retension cyst is seen in the right maxillary sinus.