A Case of Histoplasmosis Detected Through Bone Marrow Analysis

Histoplasmosis is an endemic infection caused by Histoplasma capsulatum, leading to a broad spectrum of disease from asymptomatic to severe disseminated disease. To diagnose Histoplasmosis, culture remains the gold standard for the laboratory diagnosis; however, this fungus grows slowly, taking a long time 2 to 3 weeks or may take up to 8 weeks. Therefore, some other methods such as bone marrow examination play an essential role in rapid identification and early diagnosis, especially in cases of severe disseminated disease. In this case, we report a 55-year-old man with a 1-year history of gout, self-medicating (including Medrol) who was admitted to the hospital because of persistent fever and swelling of his left arm. About laboratory investigation, there was a bicytopenia (RBC and PLT), blood and pus cultures many times were negative. On the slide of the bone marrow specimen, images of yeast suspected of Histoplasma capsulatum were observed. Therefore, the patient was treated with antifungal medication, and the culture was repeated with prolonged follow-up time and positive results with H. capsulatum after 16 days. In conclusion, bone marrow test plays a significant role in the diagnosis of some fungal infections, which can contribute to an early diagnosis, especially in cases of culture and serological tests are not available or cannot be performed. Patients who present with fever and bicytopenia or pancytopenia should be performed early bone marrow test, which can support the earlier diagnosis to have appropriate treatment.