Which clinical history findings are characteristic of cystic lesions of the knee?

Updated: Dec 29, 2018
  • Author: David M Gonzalez, MD, FACS; Chief Editor: Thomas M DeBerardino, MD  more...
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Answer

The clinical presentation of the more common cysts about the knee is that of a nonpainful or minimally painful soft mass. The location depends on which extra-articular structure is involved. Popliteal cysts, as shown in the image below, usually present as a nonpainful posterior popliteal mass. Patients may also have intra-articular knee symptoms, as well. When pain is present, it is most often due to the intra-articular process that is responsible for the popliteal cyst. Children usually present with a nonpainful mass that is noticed by an adult.

Popliteal cyst. Courtesy of James K. DeOrio, MD, L Popliteal cyst. Courtesy of James K. DeOrio, MD, Laura W. Bancroft, MD, and Jeffrey J. Peterson, MD.

Swollen and inflamed bursae can be painful. Prepatellar bursitis, as shown in the image below, can occur following repetitive trauma of recurrent kneeling, is often occupation-related, and can degenerate and become infected in the acute setting. A pes anserinus bursa, an infrapatellar bursa, and a collateral ligament bursa can also appear as painful, swollen masses in their respective areas.

Prepatellar bursitis. Sagittal T2-weighted magneti Prepatellar bursitis. Sagittal T2-weighted magnetic resonance image shows a fluid collection (arrow) anterior to the patella. Courtesy of William B. Morrison, MD.

Meniscal cysts, as shown in the images below, most often manifest as pain that is aggravated by activity. These are sometimes palpable, most often on the lateral side, along the anterolateral aspect of the knee joint. Meniscal cysts are more difficult to palpate on the medial side of the knee because they tend to dissect in the tissue planes.

Meniscal cyst. Courtesy of James K. DeOrio, MD, La Meniscal cyst. Courtesy of James K. DeOrio, MD, Laura W. Bancroft, MD, and Jeffrey J. Peterson, MD.
Meniscal cyst. Coronal T2-weighted magnetic resona Meniscal cyst. Coronal T2-weighted magnetic resonance image shows a cyst (arrow) adjacent to the lateral meniscus (arrowhead) and also demonstrates a tear communicating with the cyst. Courtesy of William B. Morrison, MD.

Other less common benign cysts about the knee, such as intraneural cysts of the common peroneal nerve, present with pain and sensory changes in the anterior tibial nerve along the anterior aspect of the leg and dorsum of the foot. The muscles of the anterior compartment of the leg can also be involved, manifesting clinically as a footdrop. Patients with cystic adventitial disease of the popliteal artery have been reported to present with intermittent claudication. [15]


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