A Case of Allergic Bronchopulmonary Mycosis Caused by <i>Curvularia mebaldsii</i>

An 18-year-old man was referred to our hospital by his family doctor after noticing an abnormal shadow on chest radiography during a health checkup. He did not report respiratory complaints during his first visit to our hospital. Computed tomography of the chest revealed a highly absorptive, club-shaped, bifurcated shadow in the right upper lobe and surrounding granular shadows, indicating a mucus plug. Bronchoscopy revealed edematous changes in the bronchial epithelium of the right upper lobe and viscous white sputum in the right B3 bronchus. When a sputum sample was collected using biopsy forceps, a mass of the mucus plug was suspected. A filamentous fungus was detected in the culture test, and an identification test performed at Chiba University Mycological Medical Research Center identified it as Curvularia mebaldsii. On the basis of the new diagnostic criteria proposed by the Japanese allergic bronchopulmonary mycosis (ABPM) research team in 2019, we diagnosed the condition as ABPM caused by this fungus. This is the first report of ABPM caused by C. mebaldsii in Japan within the scope of our search. The new diagnostic criteria proposed by the ABPM research team were useful for diagnosing this case.