Magnetic resonance imaging appearance of soft-tissue metastases: our experience at an orthopedic oncology center

Objective To assess the prevalence and magnetic resonance imaging appearance of metastasis presenting as a soft-tissue mass. Materials and methods A retrospective chart review was performed on 51 patients who presented to an orthopedic oncology center with soft-tissue masses, with a histology-proven diagnosis of soft-tissue metastasis, over a 14-year period. Their magnetic resonance imaging, primary origin, and follow-up have been assessed. Results Soft-tissue metastasis was identified in patients ranging from 18 to 85 years old. Most (80%) of the masses were located deep to the deep fascia. In our cohort of patients, melanoma was the most common primary malignancy contributing to soft-tissue metastasis (21.8%). Among soft-tissue metastasis from solid organs, breast and lung were the most frequent (9.1% each). Five patients had soft-tissue metastases from an unknown primary. Conclusion Imaging diagnosis of soft-tissue metastases is challenging as it can demonstrate imaging appearances similar to primary soft-tissue sarcoma. The presence of a known malignancy may not be evident in everyone, and even if available, histopathology will be necessary for diagnosis if this is the only site of recurrence/metastasis to differentiate from a primary soft-tissue sarcoma. Moreover, soft-tissue metastasis may be the initial presentation of a malignancy. Primary malignancies with soft-tissue metastasis carry a poor prognosis; hence, prompt diagnosis and management in essential.