A Case of Myeloid Sarcoma Misidentified as a Benign Tumor by Ultrasound

ABSTRACT Myeloid sarcoma (MS) is a rare solid malignant tumor formed by the proliferation and infiltration of primitive granulocytes or immature myeloid cells in extramedullary tissues. MS is usually associated with acute myeloid leukemia. MS can occur in any part of the body, and this case involves multiple occurrences in the lower leg. There are currently few reports on the ultrasonic manifestations of MS. In this case, the initial ultrasound findings suggested a benign lesion, which was inconsistent with the patient's known history of AML. However, the decision to perform a biopsy led to the correct diagnosis of MS. This case highlights the deceptive ultrasound features of MS and underscores the critical importance of histological confirmation in cancer patients with any new mass, regardless of its benign imaging appearance.