Reversed halo sign in invasive fungal infections.

Recent studies conducted in Brazil(1-3) have stressed the importance of the reversed halo sign (RHS) in the diagnosis of lung diseases in immunocompetent patients. However, the RHS in immunocompromised patients has not received the same emphasis. Here, we report the case of a 51-year-old female patient who presented with a 10-day history of generalized ecchymosis and weakness. A complete blood count revealed a hemoglobin concentration of 9.0 g/dL, a white blood cell count of 60 × 109/L, a neutrophil count of 1 × 109/L (peripheral blasts, 20%), and a platelet count of 80 × 109/L. A diagnosis of acute leukemia was suspected. A bone marrow biopsy was performed and confirmed a diagnosis of acute myeloid leukemia. Treatment was started with cytarabine and daunorubicin. The patient experienced dry cough and right-sided pleuritic pain during the treatment period. A CT scan of the chest showed a right upper lobe mass with the characteristics of an RHS (Figure 1). Bronchoscopy revealed no abnormalities. Aspergillus fumigatus was isolated by cultures from an open lung biopsy sample. The patient was started on oral voriconazole and responded well to treatment, with symptom improvement and resolution of the pulmonary lesion. The RHS is a chest CT finding defined as a focal, rounded area of ground-glass opacity surrounded by a nearly complete ring of consolidation. The RHS has been reported in a wide spectrum of diseases, including noninfectious diseases and infectious diseases such as invasive fungal infections (IFIs).(4,5) Because of this broad differential diagnosis, the RHS is considered a nonspecific sign. However, certain morphological characteristics of the RHS can aid in establishing a diagnosis. In immunocompromised patients, a reticular pattern within the halo and a thick rim of consolidation are highly suggestive of IFI.(4,5)