Presentation and Findings: 45 year old female presents with an increasing growth on the right neck. CT scan was done that demonstrates an extremely large heterogeneous mass in the right supraclavicular region. Findings are consistent with a high grade sarcoma of the sternocleidomastoid muscle. Specifically, this lesion is consistent with rhabdomyosarcoma of muscular origin.

Key Points: Soft-tissue sarcomas are malignant lesions that originate from soft tissues. Rhabdomyosarcomas arise from muscle cells. Rhabdomyosarcomas are most commonly found in children and account for up to 10% of childhood malignancies and 20% of all pediatric soft tissue sarcomas. There is a slight male predominance of incidence of sarcomas. Clinical presentation will vary on the location of a tumor – in this case, rhabdomyosarcomas are rapidly growing masses with mass effect on neurovascular structures with extensive infiltration often seen of adjacent structures including bones and adjacent organs. Rhabdomyosarcomas can occur anywhere but particularly where skeletal muscle is located. Most common locations include head, neck and pelvis.

Case submitted by Dr. Kay Ogenda MD, radiologist to radRounds Radiology Network