A Case of Antineutrophil Cytoplasmic Antibody (ANCA) - Negative Eosinophilic Granulomatosis with Polyangiitis (EGPA) with Nasal Polyps and Peripheral Neuropathy.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a necrotizing vasculitis that affects small and medium-sized blood vessels, characterized by asthma, blood and tissue hypereosinophilia, and the presence of extravascular eosinophilic granulomas. In 30% to 40% of patients, antineutrophil cytoplasmic antibodies (ANCAs) can be detected in the blood, which classifies the disease as ANCA-associated vasculitis. However, according to the classification criteria by the American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR), detecting ANCAs in the blood is not a criterion for this disease. We present a case of a 34-year-old woman with chronic rhinosinusitis (CRS) with nasal polyps, asthma, hyposmia, elevated body temperature, weakness, loss of sensation in the feet and hands, and difficulty walking. Neurological diagnostics pointed to an asymmetrical polyneuropathy. Histological analysis of tissue samples from the nasal cavity showed the presence of extravascular hypereosinophilia, where the accumulation of activated eosinophils was most pronounced in the tissue of nasal polyps. EGPA should be considered in cases of refractory CRS with nasal polyps, asthma, peripheral neuropathy, and histological findings of extravascular tissue eosinophilia.