Infantile Disseminated Bacille Calmette–Guérin Disease with Hemophagocytosis and Mimicking Juvenile Myelomonocytic Leukemia: A Case Report with Concise Literature Review

Bacille Calmette–Guérin (BCG) is a live‑attenuated vaccine routinely administered to newborns to prevent severe forms of tuberculosis (TB) in TB‑endemic countries. Disseminated BCG vaccine disease is a classic feature of children with human immunodeficiency virus (HIV) or primary immunodeficiency disorders (PIDs) and is associated with high mortality. We report a case of a 6‑month‑old infant with disseminated BCG disease and hemophagocytic lymphohistiocytosis mimicking juvenile myelomonocytic leukemia with no demonstrable features of HIV or PID even after extensive laboratory work‑up and succumbed to progressive disease. Disseminated BCG disease is a rare and potentially fatal complication of BCG vaccine, and prompt immunological evaluation complemented by initiation of 4‑drug antitubercular therapy and definitive treatment with antiretroviral therapy or hematopoietic stem cell transplant is warranted.