Disseminated Blastomycosis as an Infiltrating Spinal Mass Mimicking Malignancy

This is a case of a young immunocompetent man with upper back pain and imaging of an infiltrative vertebral mass diagnosed with disseminated blastomycosis after a surgical pathology and cultures who was treated successfully with antifungal therapy. It highlights the diagnostic challenges of blastomycosis because of limited clinician familiarity, even in endemic regions, low clinical suspicion as the result of atypical presentations, imaging overlap with malignancy, and infection in healthy individuals without significant exposure history. The report emphasizes the importance of considering fungal infections in the differential diagnosis of infiltrative skeletal lesions, particularly in endemic regions where blastomycosis remains underdiagnosed and underreported.