[18F]FDG PET/CT guided biopsy confirms diagnosis of granulomatosis with polyangiitis.

A 55-year-old man with a prior medical history of chronic sinusitis was referred due to progressive dyspnea and weight loss. Computed tomography (CT) of the chest revealed multiple consolidations in both lungs. For further work-up, positron remission tomography/CT (PET/CT) with [18F]fluoro-D-glucose ([18F]FDG) was subsequently performed demonstrating high [18F]FDG uptake in the nasal cavity (SUVmax: 16.9). In addition, intense tracer accumulation in the aforementioned lung lesions (SUVmax: 21.9) was observed (▶ Fig. 1). Biopsies of the nasal septum and the lungs were performed. Pathologic workup revealed acute and chronic inflammation with granulomatous features (▶ Fig. 2), confirmed by the presence of anti-neutrophil cytoplasmic antibodies in serum. A diagnosis of granulomatosis with polyangiitis (GPA) was established, and anti-inflammatory therapy consisting of high dose prednisolone and rituximab was initiated.