Hemophagocytic Lymphohistiocytosis: A Confusing Problem of the Diagnosis of Visceral Leishmaniasis

Excerpt

15-month-old boy was referred to our clinic for evaluation of fever and pancytopenia for 10 days. Physical examination was normal except pallor and hepatosplenomegaly (HSM). Laboratory investigation revealed hemoglobin 7.9 g/dL, leukocyte count 3.2 × 10⁹/L, absolute neutrophil count 0.6 × 10⁹/L and platelet count 35 × 10⁹/L. The peripheral blood smear demonstrated 10% atypical lymphocytes resembling virocytes; other blood cells were normal appearance. Serum lactate dehydrogenase level was 1596 U/L, triglyceride 262 mg/dL, fibrinogen 102 mg/dL, and ferritin level was 9356 ng/mL. Vitamin B12 level was very low (65 pg/mL). There was no serological evidence of infection, such as hepatitis A, hepatitis B and hepatitis C, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, and toxoplasmosis. The first bone marrow aspirate was hypercellular with the presence of dysmyelopoiesis, numerous histiocytes engulfing erythroid cells, neutrophils and lymphocytes leading to a suspicion of hemophagocytic lymphohistiocytosis (HLH) (Fig. 1). No parasites were detected.

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