Fever and Cavitary Lung Lesion in an Adolescent: A Case of Histoplasmosis

Background: Cavitary pulmonary lesions in pediatric patients are uncommon and have a broad differential diagnosis, including bacterial necrotizing pneumonia, tuberculosis, septic emboli, and fungal infections. Histoplasmosis is an endemic fungal infection that typically causes mild respiratory illness in children, and cavitary disease in immunocompetent hosts is rare. Case Presentation: A 13-year-old previously healthy female presented with fever, cough, chest pain, and shortness of breath. Initial evaluation revealed leukocytosis, tachycardia, and an elevated D-dimer. Chest imaging demonstrated a left upper lobe cavitary lesion with an additional area of consolidation. Pulmonary embolism was excluded on chest CTA, and she was started on empiric broad-spectrum intravenous antibiotics for presumed severe pneumonia. Septic emboli were subsequently ruled out with echocardiography and negative blood cultures. Despite treatment, she remained intermittently febrile. Extensive infectious evaluation was negative for tuberculosis and other common bacterial and viral etiologies. On hospital day 6, urine Histoplasma antigen returned positive, confirming acute pulmonary histoplasmosis. Antibacterial therapy was discontinued, and antifungal therapy was initiated. Because of evidence of disseminated infection, the patient was transferred for a higher level of care. Conclusion: This case highlights the importance of considering histoplasmosis in pediatric patients with cavitary lung lesions, particularly in endemic regions. Early use of urine antigen testing can expedite diagnosis, avoid unnecessary invasive procedures, and enable timely, targeted therapy.