Objective: The purpose of this article is to describe the image findings of distant metastases to skeletal muscle with clinical correlation.
Design and patients: The records of nine consecutive patients with biopsy-proven metastases to skeletal muscle from primary malignancies were retrospectively reviewed for clinical history and findings from magnetic resonance imaging (MRI) (eight cases) or computed tomography (CT) (one case). Clinical history, interval between detection of primary tumor and metastases, multiplicity, primary cell type of malignancy, site of metastases, and nature of masses on MRI or CT were evaluated by two musculoskeletal radiologists.
Results: The most common symptom was a painful mass (78%), and the most common site was the thigh (78%). Four patients showed a single mass (44%). There was previous malignancy in five patients (56%), but four patients had no prior malignancy (44%). The time interval between the detection of primary malignancy and metastases was 8 months to 15 years. Mean size of metastases was 5.1 +/- 2.2 cm. The most common primary tumor was of the lung (two patients) and kidney (two patients), and the most common cell type was adenocarcinoma. On images, necrosis and peritumoral edema were relatively frequent. All cases showed good enhancement. of contrast medium.
Conclusion: Skeletal muscle metastases show good enhancement of contrast medium and frequent edema and necrosis. The possibility of skeletal muscle metastases should be borne in mind for patients with painful and multiple muscle masses.