Background: Aspergillosis is an infection caused by a common mold (type of fungus) named Aspergillus. Its spores are present in air but usually do not cause any disease in immune-competent people. However, it can cause various types of diseases, which most commonly involve the respiratory system. Early recognition and treatment are important for better outcomes. Case Presentation: A middle-aged diabetic male presented with high blood glucose levels leading to hyperosmolar hyperglycemic non-ketotic coma and was treated accordingly. His baseline chest X-ray showed reticulo-nodular shadowing and cavitatory lesion in left middle zone and was being treated on the lines of pneumonia. After 4 days of treatment, the patient did not improve and had had contrast enhanced CT-scan chest showing a reverse halo sign along with a fungal ball in the lung cavity. His white blood cells were increased, erythrocyte sedimentation rate was normal, and sputum for acid-fast bacilli was negative, but positive for Aspergillus species. Conclusion: Diagnosis of pulmonary aspergillosis was made and the patient was managed accordingly with intravenous antifungal therapy. Early diagnosis and treatment is necessary.

Keywords: Aspergillosis, reverse halo sign, aspergilloma, diabetes