Primary Hematopoietic and Lymphoid Tissue ›› Bone Marrow ›› Abnormal Histoplasmosis in Histiocytes* Click Here for Full Size › Microscopic Features: Small round fungal forms seen within the cytoplasm of mature monocytes and histiocytes › Normal % blood-PB, marrow-BM, lymphoid tissue-LN: PB: None BM: None LN: None › May Resemble: Leishmania in Histiocytes Cellular debris in Histiocytes Bacteria in Histiocytes › Differential Diagnoses: Histoplasmosis Leishmaniasis Cellular debris within histiocytes Bacterial infection › Classic Immunophenotype: N/A › Cartoon Image: Click and drag for direct comparison › Misc: Histoplasma fungal forms lack kinetoplasts (small dark blue rod shaped structures within the organism) which are present in leishmania