Lateral Meniscus Cyst

about ultrasound appearance of lateral meniscus cyst degeneration

In my previous post Meniscal Cyst I showed the ultrasound appearance of a medial meniscus cyst, together with a suspected meniscal tear. Today I present the case of a young football player that came to my observation one year after a lateral collateral partial strain injury. As you certainly know peripheral attachments of the lateral meniscus are more lax than on the medial side, permitting greater mobility of the lateral meniscus.


The dynamic ultrasound exam allows to appreciate a gross meniscal fissuring, with a meniscal cyst and partial extrusion; no alterations were seen along the course of the lateral collateral ligament.

Meniscus extrusion is usually associated with meniscal degeneration and tears, so it is crucial to always perform also the Mri examination.


Coronal T2w (left) and Axial T2w (right) Mri scans (0.3 Tesla). The meniscal cyst and degeneration are evident.


Coronal T2w (left) and Axial T2w (right) Mri scans (0.3 Tesla). Complex tear of the lateral meniscus.


Meniscal Cyst

Today I want to show you the case of a patient that comes to me for an ultrasound examination of a palpable mass adjacent to the postero-medial compartment of the knee joint, with an history of a major knee inury five years before; the sonographic findings reveal a well defined cystic lesion and associated meniscal tear.

Always ask for an Mri investigation to better evaluate the real extent of the meniscal tear; don’t trust only ultrasound!

The Mri exam perfectly depicts the cyst and the meniscal complex tear with gross mucoid degeneration.


Coronal (left) and Axial (right) T2 weighted Mri scans (0.3 tesla).


Ge Stir (left) and T1 weighted sagittal Mri scans (0.3 tesla) of the same patient.