Supplementary Material for: Acute Myeloid Leukemia Presenting as a Cardiac Mass

Leukemias are the most common childhood malignancy. It is a systemic disease presenting with different signs and symptoms. Extramedullary manifestations, in particular myeloid sarcoma (MS), are extremely rare, often challenging to identify, even more challenging to diagnose, and more than often misdiagnosed owing to its similarity with other solid tumors. We describe a previously healthy boy, aged 4 years, who had a cardiac mass lesion, presumed to be a MS, noted in the right atrium at the time of initial routine echocardiography. The lesion resolved without surgical intervention following the institution of multi-agent chemotherapy.

白血病是儿童最常见的恶性肿瘤。其为一类伴随多样体征与症状的全身性疾病。髓外表现（extramedullary manifestations）极为罕见，其中尤以髓系肉瘤（myeloid sarcoma, MS）为甚，该类病变常难以识别，诊断难度更高，且由于其与其他实体瘤相似，往往容易被误诊。本文报告一例既往健康的4岁男童，在初次接受常规超声心动图检查时，于右心房发现一处心脏占位性病变，初步推测为髓系肉瘤。在予以多药联合化疗后，该病变未行手术治疗便得以消退。