Learning objectives
1) In this pictoral essay,
we explore different types cystic lesions that can be found whilst imaging the knee joint.
These can be broadly divided as follows:
Cyst of theknee joint
Ganglion
Meniscal
Bursal
Subchondral
Post-operative
Cyst-like lesion of the knee joint
Neurovascular lesion
Cystic adventitial disease
Synovial haemangioma
Tumours mimicking cyst
Morel-Lavellee lesion
2) Review pathophysiology of the cystic lesion and its appearance.
3) Understand the important imaging features that will aid in correct diagnosis of the given lesion.
Background
Knee is the most commonly examined joint in musculoskeletal imaging. There are therefore wide range of findings that are both unexpected or part of an expected disease process. Many pathology will produce cystic lesion around the knee joint and correct identification and diagnosis is imperative in order to prevent unnecessary follow-up imaging,
arthroscopy and biopsy.
Imaging findings OR Procedure Details
Cysts of the knee joint
Ganglion cyst (Figures 1 - 8)
Ganglion cyst is a non-malignant cystic lesion commonly associated with musculoskeletal structures.Histology demonstrates thin connective tissue capsule with no synovial lining and contains gelatinous fluid that is rich in hyaluronic acid and other mucopolysaccharides(1).
Although its exact aetiology is unknown,
it is thought to be secondary to mxyoid degeneration of connective tissue and can be broadly divided into intra-articular and extra-articular ganglion cysts.
Intra-articular cyst:Commonly associated with the anterior cruciate ligament,
which is an...
Conclusion
Cystic lesions are common around the knee and can be either truly cystic or lesions that mimic cysts.
We have identified certain image findings that would aid in the correct diagnosis of cysts or cyst-mimicking lesions.
Radiologists should be aware of otherassociated findings that would help in identifying the nature of the cystic lesions.
Correlation with other modalities and contrast enhanced imaging maybe required in order to come to a correct diagnosis.
References
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Association of parameniscal cysts with underlying meniscal tears as identified on MRI and arthroscopy.
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Synovial cysts (ganglia) of the bone: report of two cases.
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