Differential Diagnosis for Intrameniscal Cyst within the Lateral Meniscus
Single Most Likely Diagnosis
- Meniscal tear: The presence of an intrameniscal cyst is highly suggestive of a meniscal tear, as these cysts often form as a result of the degeneration and tearing of the meniscus.
Other Likely Diagnoses
- Meniscal degeneration: Intrameniscal cysts can also be associated with degenerative changes in the meniscus, which may not necessarily involve a discrete tear.
- Lateral meniscus injury: Given the location of the cyst, an injury to the lateral meniscus, which could include a tear or other forms of damage, is a plausible diagnosis.
Do Not Miss Diagnoses
- Osteochondritis dissecans: Although less likely, osteochondritis dissecans (a joint condition in which a piece of cartilage, along with a thin layer of the bone beneath it, comes loose from the end of a bone) could potentially present with similar symptoms and should not be overlooked due to its potential for significant morbidity if left untreated.
- Septic arthritis: Infection within the joint (septic arthritis) is a serious condition that requires prompt diagnosis and treatment. While an intrameniscal cyst does not directly suggest infection, any condition causing joint pain and swelling warrants consideration of this diagnosis to avoid missing a potentially life-threatening or limb-threatening condition.
Rare Diagnoses
- Synovial chondromatosis: A rare condition characterized by the growth of cartilage in the synovium, which could potentially cause cystic changes within the meniscus or other joint structures.
- Pigmented villonodular synovitis (PVNS): A rare disease that affects the synovium, leading to overgrowth and potential cyst formation within the joint, including the meniscus.