Disease in disguise – An unusual cause of leukocytosis in an infant – A case report and review of the literature

Leukocytosis with cytopenias of other cell lines and organomegaly in children pose a significant diagnostic challenge. Leukemoid reaction is exaggerated leukocytosis, whereas misinterpretation of nucleated red blood cells (nRBC) leads to spurious leukocytosis. These need to be considered in given clinical context to investigate further appropriately. We describe a report of 6 months infant who was referred with suspected acute leukemia based on initial evaluation when he presented with severe pallor and hepatosplenomegaly with white blood cell >50× ×109/L. He was later found to have spurious leukocytosis with an underlying hemolytic anemia. The strikingly normal platelet count, absence of blasts in smear and low mean corpuscular volume for age gave initial clues away from leukemia. This case emphasizes the need for systematic approach to clinical features followed by meticulous analysis of every parameter of hemogram and peripheral smear to arrive at appropriate diagnosis and to avoid unnecessary investigations.