Acute leukemia is a potentially curable hematopoietic malignancy characterized by an absolute increase in total body immature leukocytes. Acute lymphoblastic leukemia (ALL) is the most common malignancy diagnosed in children. Here, we present a
case of sinusitis as initial presentation of acute lymphoblastic leukemia. An 8-year-old Taiwanese boy with right facial swelling for two weeks was managed conservatively under the impression of acute sinusitis. However, his right facial swelling persisted despite surgical intervention and intravenous antibiotics treatment. Followed-up lab data showed hyperleukocytosis (white blood cell count: 30.99*10^3/uL, blast form 50%, neutrophils 30%, lymphocyte 14%). Third weeks after admission, acute lymphoblastic leukemia was then diagnosed. This case illustrated rare, aggressive diseases such as acute lymphoblastic leukemia can masquerade as simple subacute sinusitis without typical signs like fever, pallor, bleeding tendency or fatigue. (J Taiwan Otolaryngol Head Neck Surg 2023; 58:69-74)
