An Extra-articular Ganglion Cyst with Multiple Fluid-Fluid Levels.

INTRODUCTION: Ganglion cysts are the knee's most common benign soft tissue tumors. Ganglion cysts are seen as multiloculated fluid collections on magnetic resonance imaging (MRI), and fluid-fluid levels are not an expected finding.

CASE PRESENTATION: A 36-year-old female patient presented with swelling in her right knee. Magnetic resonance imaging revealed a multiseptated cyst with multiple fluid-fluid levels within the anterior of the right patellar tendon. Open surgical excision was performed, and the pedicle of the cyst was dissected. The histopathology revealed a ganglion cyst with hemorrhage.

CONCLUSION: The ganglion cysts should be considered in the differential diagnosis of lesions with fluid-fluid levels, in addition to hemangioma, synovial sarcoma, and aneurysmal bone cysts of soft tissues.