Very painful acute frontal sinusitis revealing granulomatosis with polyangiitis.

INTRODUCTION: Granulomatosis with polyangiitis (GPA) is a necrotizing vasculitis of small and medium-sized vessels comprising inflammation of the vessel wall and perivascular and extravascular granulomas, frequently presenting in the form of chronic sinusitis. OBSERVATION: We report the case of a 27-year-old man who presented with very painful acute frontal sinusitis that was managed medically and surgically. The symptoms rapidly recurred despite treatment and CT scan demonstrated diffuse thickening of the sinus mucosa. Anti-proteinase 3 ANCA were positive. Biopsy of a pulmonary nodule confirmed the diagnosis of GPA. The patient was treated with corticosteroids in combination with rituximab, resulting in improvement of the clinical, laboratory and CT signs. DISCUSSION: In the presence of persistent, acute, localized sinusitis despite appropriate treatment, associated systemic signs and/or the presence of other signs suggestive of GPA, the ENT surgeon must request a targeted work-up. In the absence of treatment, GPA can be fatal within a few months. However, with currently available treatment, remission is obtained in 80% of cases with a 75% 10-year survival rate.