Radiological markers of granulomatosis with polyangiitis with nasal involvement.

INTRODUCTION: Granulomatosis with polyangiitis (GPA) is an autoimmune disease leading to necrotizing lesions in the affected tissues. Computed tomography (CT) of paranasal sinuses reveals multiple lesions in patients with GPA, for example, sinus opacification, bone / cartilage destruction, and neoosteogenesis. OBJECTIVES: We aimed to describe and compare CT lesions found in patients with GPA and those with chronic rhinosinusitis (CRS) and to propose a new radiological marker of GPA-nasal strands. PATIENTS AND METHODS: This retrospective study (2014-2019) included 53 patients with GPA (22 men, 31 women) at a median (interquartile range) age of 45 (34-60) years. Computed tomography findings of mucosal lesions in paranasal sinuses, neoosteogenesis, bony and cartilaginous lesions, and nasal strands were analyzed. Nasal strands were described as intermucosal adhesions resembling bands. A total of 71 patients with CRS (reference group) were assessed for the presence of the same parameters. RESULTS: Computed tomography scans showed mucosal lesions in the sinuses of 35 patients (66%) with GPA. Nasal septum perforation was observed in 19 patients (35.8%), neoosteogenesis in 17 (32.1%), and bone damage in 14 (26.4%). External nose deformity was present in 16 patients (30.2%). Nasal strands on CT were found in 36 patients with GPA (68%) and 32 patients with CRS (45%). The presence of 5 or more strands was more characteristic of GPA than CRS (P <0.001). A positive correlation was found between the number of strands greater than or equal to 5 and the presence of proteinase 3 antineutrophil cytoplasmic antibodies (P = 0.046). CONCLUSIONS: Nasal strands, a parameter reflecting pathologic mucus and atrophic lesions (tissue loss), should have a place in CT evaluation of the nasal cavities in patients suspected of or diagnosed with GPA.