From Syphilis to Surprise: Unmasking Disseminated Blastomycosis in a 20-Year-Old Male.

Blastomycosis is a systemic endemic fungal infection caused by Blastomyces dermatitidis, a dimorphic fungus, that predominantly affects the lungs but can disseminate to other organs, mimicking many diseases, making diagnosis challenging. We present a case of disseminated blastomycosis in a male, initially misdiagnosed as syphilis due to a false positive biopsy result for Treponema pallidum. This case highlights the importance of considering atypical presentations of fungal infections, even in the presence of laboratory findings and outside of the normal geographic regions they may be found.