Histoplasmosis is rarely seen in Taiwan and only a limited number of cases have been reported locally. We reported a 37-year-old man, a Myanmar immigrant, with established pulmonary histoplasmosis. No known risk factors, such as AIDS or immunosuppressive therapy, were identified. The patient willingly refused antifungal therapy of uncertain efficacy, which provided the opportunity to observe the evolution of untreated pulmonary histoplasmosis. Furthermore, this case serves as a reminder for clinicians to always consider alternative diagnoses when the clinical course of a disease does not evolve as expected.