A Runny Nose Leads to a Rare Diagnosis: Chronic Sinusitis as a Sole Manifestation of Limited Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated necrotizing vasculitis of small to medium-sized blood vessels. The typical presentation is the classic triad of upper airway, pulmonary, and renal involvement. However, it can rarely present with the involvement of a single organ system known as limited granulomatosis with polyangiitis. We present a case of a 53-year-old male with chronic rhinosinusitis as the only manifestation of limited GPA. The diagnosis was established incidentally based on biopsy findings from the paranasal sinuses obtained during functional endoscopic sinus surgery. Subsequent testing revealed a positive cytoplasmic antineutrophilic antibody. No evidence of systemic involvement was noted. Prednisone and azathioprine were initiated leading to significant improvement. Although upper respiratory tract involvement is common in GPA, it is rare for the condition to be limited to this organ system. Our case of limited GPA is distinct in that it represents a rare presentation of this already rare disease.