Fig 1.
The mapping scheme for localization of TSGCT.
The intraarticular space is divided into three points including SP (suprapatellar pouch), AC (anterior compartment), and iP (posterior compartment). The extraarticular space is divided into three points including eP (posterior to joint capsule), DP (direct posterior to joint capsule), and BJ (below the joint capsule).
Fig 2.
Definition of the MRI features relating to the disease subtypes.
(A) Pathology-proven D-TSGCT shows that the intraarticular mass (iP, arrow) extending to subpopliteal recess (DP, *), and some parts have crossed to an extraarticular location (eP, **). The masses contain two or more distinct nodules, classified into type II nodularity with infiltrative margin from surrounding tissues. The representative mass (**) shows the granular internal hypointensity without peripheral hypointensity. (B) This mass shows an villonodular and infiltrative margin and abundant hemosiderin-laden macrophages through the tumor (H&E, X40). (C) Pathology-proven L-TSGCT shows the intraarticular (iP, arrow) single nodule, classified into type I nodularity. The mass shows a circumscribed margin from surrounding tissues and a speckled internal hypointensity with peripheral hypointensity. (D) This mass shows a well-circumscribed mass entirely enveloped by a thin fibrous septa and a scant amount of hemosiderin deposit (H&E, X40).
Fig 3.
MRI features regarding disease subtypes.
(A) Sagittal T2-weighted image of a 24-year old woman with intraarticular D-TSGCT shows soft tissue masses that are very low signal intensity located in knee joint (arrows) showing infiltrative margin and containing granular internal hypointensity without visible peripheral hypointensity. Note that the lateral femoral condyle cartilage injury is combined (arrowhead). (B) Sagittal T2-weighted image with fat suppression of a 26-year old woman with intraarticular L-TSGCT shows soft tissue mass at the posterior femoral recess (arrow). Note that the mass shows a circumscribed margin and contains a speckled internal hypointensity with peripheral hypointensity. (C) Axial T2-weighted image with fat suppression of a 40-year old woman with extraarticular D-TSGCT shows soft tissue masses that are very low signal intensity at the insertion of the pes anserinus conjoined tendon (arrows) presenting the multinodular masses with infiltrative margin with bone invasion (*) and containing granular internal hypointensity (arrows) without visible peripheral hypointensity. (D) Axial T2-weighted image with fat suppression of a 30-year old man with extraarticular L-TSGCT shows soft tissue masses along the pes anserinus conjoined tendon (arrows) presenting a circumscribed margin and containing a speckled internal hypointensity (arrows) with peripheral hypointensity.
Table 1.
MRI findings between L-TSGCT and D-TSGCT.
Fig 4.
A 29-year old woman with pathology-proven extraarticular D-TSGCT of knee.
(A and B) Preoperative sagittal and axial T2-weighted images with fat suppression show soft tissue mass that are very low signal intensity located in the extraarticular posterolateral aspect of knee with infiltrative margin containing granular internal hypointensity without visible peripheral hypointensity (arrows). Note that the lateral femoral condyle cartilage is involved by tumor (arrowhead). (C and D) Follow-up MRI after 30 months show recurrent mass with same nature (arrows).
Table 2.
Logistic regression analysis of MRI parameters predicting D-TSGCT.
Table 3.
MRI findings regarding disease severity associated with local recurrence.
Fig 5.
A 19-year old woman with pathology-proven intraarticular L-TSGCT of knee.
(A and B) Preoperative sagittal and axial T2-weighted images show soft tissue mass located in the Hoffa’s fat pad with circumscribed margin containing granular internal hypointensity without visible peripheral hypointensity (arrow). Note that the patellar tendon is involved by tumor (arrowhead). (C) Follow-up ultrasound after 13 months show recurrent mass (arrow).
Fig 6.
MRI parameters tree to predict local recurrence.
MRI parameters begin with the margin followed by tendon involvement with sensitivity, 100%; specificity, 50%; accuracy, 65%.
Table 4.
Logistic regression analysis of MRI parameters predicting local recurrence.