Differential Diagnosis for Ovoid Filling Defect
- Single most likely diagnosis
- Meniscal cyst: This is the most likely diagnosis given the location of the filling defect, which is anteromedial to the posterior root attachment of the medial meniscus. Meniscal cysts are known to occur in this region and can present as ovoid filling defects on imaging.
- Other Likely diagnoses
- Ganglion cyst: These cysts can occur in the same region and may present similarly to meniscal cysts. They are benign lesions that can cause symptoms due to their location and size.
- Synovial cyst: Although less common, synovial cysts can also occur in this area and may appear as filling defects on imaging. They are typically filled with synovial fluid and can be associated with joint inflammation.
- Do Not Miss diagnoses
- Intra-articular tumor (e.g., synovial sarcoma): Although rare, it is crucial not to miss a potential intra-articular tumor, as it can have significant implications for treatment and prognosis. These tumors can present as filling defects and may be located near the meniscus.
- Infection (e.g., abscess): An intra-articular abscess can present as a filling defect and may be located in the same region as the described lesion. Infection would require prompt diagnosis and treatment to prevent serious complications.
- Rare diagnoses
- Bursitis: Inflammation of a bursa in the region could potentially present as a filling defect, although this would be less common in the described location.
- Hemangioma: A vascular lesion such as a hemangioma could theoretically occur in this location, although it would be an uncommon finding.