Abstract
The study design includes case report and clinical discussion. The objective was to describe a rare case of a giant intramuscular myxoma (IMM) presenting as a mass in the paravertebral muscles. Myxoma is a rare benign soft tissue tumour of mesenchymal origin. Although intramuscular presentation is common, they are rare in the paravertebral muscles and are characteristically <5 cm in length. We report the clinical and imaging features in a 70-year-old woman presenting with back pain, asymmetry of the waist and a mass in right paravertebral region. This was originally misdiagnosed as a juxtafacet synovial cyst after CT-guided biopsy. The mass was excised en bloc and sent for histology. This revealed a low-grade myxoid neoplasm with features of an IMM. The patient went on to make a complete recovery. To our knowledge, this is only the fifth case of paravertebral IMM reported in the literature and at approximately 15 cm in length may be the largest encountered in clinical practice.