Histoplasma capsulatum in the Peripheral Blood Smear: A Rare Occurrence

Excerpt

A 20 year old male presented with history of pain abdomen, abdominal distention and diarrhea since 3 weeks. On examination, he had massive hepatosplenomegaly. Imaging (CECT, whole abdomen) showed changes suggestive of non-cirrhotic portal hypertension. HIV, HBsAg and HCV testing was negative. Complete haemogram revealed pancytopenia (Haemoglobin: 8.7 g/dL total leucocyte count: 2010/uL and platelet count: 17,000/uL). Peripheral smear revealed presence of small yeast-like organisms, measuring 2–4 microns with amaranth nuclei and capsule-like unstained halos around, in the cytoplasm of monocytes lying in the extreme tail-end. They were positive for Periodic Acid Schiff (PAS) and Gomori Methanamine Silver (GMS) stain (Fig. 1). Bone marrow examination revealed numerous histiocytes loaded with similar organisms with identical staining properties. Features of the organism was consistent with Histoplasma capsulatum (Fig. 2). The culture reports are still awaited. The patient was started on amphotericin B and was investigated for immunodeficiency disorders. The results were non-contributory.

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