A case of chronic granulomatous disease masquerading as leukemia: Unraveled by flow cytometric and molecular studies

Primary immunodeficiency diseases (PIDs)/inborn errors of immunity (IEI) are inheritable genetic disorders that disrupt immune cells either qualitatively or quantitatively in the performance of their functions. The case report is about a case of chronic granulomatous disease (CGD). A 10-month-old male child presented with a history of on-and-off fever, hepatomegaly (6 cm), splenomegaly (6 cm), and submandibular lymphadenopathy. On the peripheral smear, 12% of atypical cells/blasts were seen; a differential diagnosis, such as leukemoid reaction and juvenile leukemia, was considered. PIDs workup, including nitroblue tetrazolium/dihydrorhodamine (DHR) test, serum immunoglobulin assay, and lymphocyte subset analysis, was carried out as the mother gave a history of the child being unwell since 6 weeks of age. Bone marrow examination and serial peripheral smears after treatment with antibiotics ruled out leukemia. Chronic infantile leukemias like juvenile myelomonocytic leukemias should be differentiated from septic leukemoid reaction that can occur in the context of CGD. Furthermore, the authors conclude that infections can lead to normal progenitors being released into the periphery, and one should refrain from overdiagnosing these as leukemia cases.