Skeletal Muscle Metastases from Carcinomas

A Review of the Literature

Abstract

• » Bones are a common site for metastases; however, muscle metastases recently have been more commonly reported, not only as a result of the multidisciplinary approach in the treatment of these patients but also because of more sensitive imaging modalities such as positron emission tomography-computed tomography (PET-CT) that identify these lesions in early stages.
• » The most common carcinoma is lung carcinoma, with a hematogenous route of spread mainly to the axial region of the body (the psoas muscle, the gluteal muscles, and the paravertebral muscles).
• » Clinically, skeletal muscle metastases from carcinomas frequently present as painful palpable masses with or without swelling and are commonly found before diagnosis of the primary carcinoma.
• » Multiple imaging modalities, including radiographs, CT, magnetic resonance imaging (MRI), and PET-CT, have been used for diagnosis and staging, but tissue sampling is needed for a final diagnosis. The most important differential diagnosis of skeletal muscle metastases is with soft-tissue sarcomas.
• » Treatment is mainly based on chemotherapy and/or radiation; surgery is performed in cases of symptomatic lesions that fail to respond to nonoperative treatment.