Pulmonary histoplasmosis presenting with a halo sign on CT in an immunocompetent patient

Abstract

A 47-year-old man presented with dry cough, chest pain, fatigue and fever, having started 15 days prior [Sao Paulo, Brazil]. Laboratory tests revealed leukocytosis, elevated C-reactive protein levels (33 mg/litre) and hypertransaminasaemia. Computed tomography (CT) scan revealed a pulmonary nodule with a halo sign in his left lower lobe and left para-hilar lymph nodes. Histological examination of a pulmonary biopsy sample obtained during bronchoscopy showed nonspecific inflammatory alterations. Serology by counterimmunoelectrophoresis was positive for histoplasmosis. Treatment was initiated with itraconazole (400 mg/day). After 30 days, a CT scan showed that the size of the nodule was reduced by half. He showed progressive improvement of clinical symptoms and a reduction of the para-aortic adenopathy. Treatment was maintained for one year, during which he remained asymptomatic, the nodule completely disappeared, and the lymphadenopathy resolved. However, histoplasmosis by counterimmunoelectrophoresis remained positive.