What does the mass “white blob” around the ACL imply in this case? Come up with your own answer, then scroll down to see my findings.
Of course lesion is bright (except on T1), smooth oval and therefore cyst (actually a ganglion pseudocyst). Some refer to this as mucoid lesion of the ACL.
ProScan Pearl: What is implied by this lesion is abnormal friction or encroachment on femoral notch and ACL with movement (notch “impingement” or stenosis). The patient HAS a dysplasia and was born with a congenitally small dysplastic femoral notch contributing to notch impingement.
For more compelling knee case review, check out MRI Online.