18F-FDG PET/MRI of Rhinosporidiosis of the Upper Airways.

A 41-year-old man from South Asia presented with a several months' history of unilateral nasal obstruction and bleeding. At nasal endoscopy, two strawberry-like, friable, polypoid masses in the upper airways were detected. The patient's clinical trait was compatible with an infectious disease. F-FDG PET/MRI was performed to evaluate the disease extension. Two lesions occupying the nasal cavity and the nasopharynx, slightly hyperintense in T2-weighted sequences, with intense radiopharmaceutical uptake were evidenced. Endoscopic resection was performed with histopathologic diagnosis of rhinosporidiosis, a chronic granulomatous disease caused by Rhinosporidium seeberi. Although rare, rhinosporidiosis should be considered in the differential diagnoses of sinonasal hypermetabolic lesions.