Massive Idiopathic Oropharyngeal and Laryngeal Granulomatosis on FDG PET/CT.

Idiopathic granulomatosis is a rare entity and has varied manifestations and imaging findings. A 44-year-old woman with sore throat and worsening dyspnea had multiple oropharyngeal and supraglottic masses on laryngoscopic examination. FDG PET/CT demonstrated diffuse tumor-like mucosal/submucosal lesions with intense uptake involving the oropharynx, supraglottis, and hypopharynx. Surgical biopsy showed chronically inflamed granulation tissue without malignancy, necrosis, or vasculitis. All stains were negative for any organisms. The image highlights the necessity of including granulomatosis as a differential from malignancy in interpretation of FDG PET/CT showing diffuse mucosal/submucosal oropharyngeal and/or laryngeal lesions but without established diagnosis.