Cavitary Pulmonary Blastomycosis and an Incidental Retroperitoneal Ganglioneuroma Mimicking Metastatic Disease

Pulmonary blastomycosis is a fungal infection caused by <i>Blastomyces dermatitidis</i> that can present with a wide range of nonspecific pulmonary findings and, in rare cases, mimic metastatic malignancy. This case report describes a 26-year-old immunocompetent male who presented with subacute respiratory symptoms and was found to have numerous cavitary pulmonary lesions and a large infiltrative retroperitoneal mass, raising concern for disseminated malignancy, with subsequent evaluation revealing pulmonary blastomycosis and an incidental benign retroperitoneal ganglioneuroma.