Metastasis to the Skeletal Muscle from a Malignant Phyllodes Tumor of the Breast: A Case Report

Malignant phyllodes tumors are relatively rare, accounting for 0.3 to 0.9% of all tumors of the breast. This tumor metastasizes approximately 20% of the cases depending upon the histologic behavior (1). The most common site of metastasis is the lung (1). Of all possible organs, metastasis to the skeletal muscle is relatively unusual. Moreover, imaging findings of metastasis to the skeletal muscle for patients with sarcoma such as phyllodes tumors like our case have not been published in the radiology literature, to the best of our knowledge. All the previous articles were more focused on muscle metastasis from carcinoma rather than from sarcoma (2-4). Accordingly, the purpose of this article was to present the radiological findings of metastasis of a sarcoma to the skeletal muscle that we observed in a patient with malignant phyllodes tumor, including ultrasonography (US), 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT), and magnetic resonance (MR) imaging.