October 23 2022
Ganglion Cyst (Perimeniscal Cyst Or ACL Cyst) or Synovial Sarcoma? The answer is synovial sarcoma anteriorly and cyst posteriorly! Synovial sarcomas can occur intraarticularly and can have a deceptive appearance of a cyst or a large cystic component. You must have a high degree of suspicion when evaluating this type of intraarticular mass! Care must be taken when surgically treating these masses and that they are appropriately evaluated on the MRI. I suggest an MRI with and without contrast as well as appropriate T1 and T2 weighted images and proton density weighted images. One must never perform an arthroscopy in this setting without being sure it is a cyst as an arthroscopy can spread the tumor locally and systemically potentially resulting in an amputation, metastases and death!