A previously healthy 3-year-old Syrian boy presented with fever and pancytopenia with 6% circulating lymphoblastlike cells (blastlike cell [panel A] as compared with a normal lymphocyte [panel B]; original magnification ×1000, Wright-Giemsa stain). There were no skin lesions. A younger sister died a few months earlier of unknown causes. The boy was suspected of having acute leukemia. Bone marrow examination with flow cytometry phenotyping showed no evidence of acute leukemia; however, Leishmania amastigotes were identified in the aspirate (panel C, numerous Donovan bodies in bone marrow aspirate; original magnification ×1000, Wright-Giemsa stain), and biopsy (panel D, numerous Donovan bodies in bone marrow biopsy; original magnification ×400, hematoxylin and eosin stain), diagnostic of leishmaniasis. The amastigotes showed a relatively large nucleus and the characteristic deeply stained rodlike kinetoplast. Polymerase chain reaction confirmed the pathogen as Leishmania infantum.

Visceral leishmaniasis (VL) is an opportunistic life-threatening infection that usually occurs in regions of endemicity and in immunocompromised hosts. This young patient came from a region where cutaneous leishmaniasis is endemic. VL is not common, and the boy had no immunodeficiency. VL can be encountered in areas where it is not endemic and, as in this case, can clinically mimic other diseases, such as acute leukemia.