Answer
Answer
Synovial sarcoma constitutes 8-10% of all sarcomas and usually involves the extremities (as demonstrated in the images below), especially the lower extremities around the knees. Synovial sarcoma is frequently misdiagnosed as a benign condition because of its often small size, slow growth, and well-defined appearance. This malignancy is driven by a translocation between SS18 and SSX 1, 2, or 4 (hybrid transcription factor SS18:SSX). Approximately 1,000 cases a year are diagnosed n the United States, most commonly between 15 and 30 years of age. [1, 2, 3, 4, 5]
Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!
Media Gallery
-
Lateral radiograph of the foot in a 60-year-old man who presented with a mass on the dorsum of his left foot. The radiograph shows a soft-tissue mass that is anterior to the talus and without obvious underlying bone erosion. Subtle faint calcifications are seen within the mass.
-
Coronal T1-weighted magnetic resonance image of the foot in a 60-year-old man who presented with a mass on the dorsum of his left foot. A rounded, soft-tissue mass is seen eroding the cortex of the superior talus. The mass is predominantly isointense relative to the muscle, with scattered areas of hyperintensity that are consistent with hemorrhage.
-
Sagittal T2-weighted magnetic resonance image of the foot in a 60-year-old man who presented with a mass on the dorsum of his left foot. The mass shows predominantly high signal intensity that is hyperintense relative to fat. Scattered areas of hypointensity probably represent calcifications.
-
Anteroposterior radiograph of the hip in a patient who presented with a mass in the region of the left hip. Opaque, masslike calcifications overlying the femoral neck and inferior pubic ramus are seen.
-
Computed tomography scan of the hip in a patient who presented with a mass in the region of the left hip. The scan was obtained through the mass and demonstrates masslike areas of calcification within the muscle density in the region of the left obturator externus muscle.
-
Computed tomography scan through the right thigh. This image demonstrates a round, noncalcified, well-circumscribed mass that displaces, rather than invades, the surrounding muscles. The mass appears to be separate from the bone.
-
Lateral radiograph of the femur in a 45-year-old man who presented with a large, right midthigh mass. This radiograph is remarkable only for a subtle soft-tissue prominence on the anterior aspect of the thigh. No calcifications are depicted.
-
Computed tomography scan of the thigh in a 45-year-old man who presented with a large, right midthigh mass. A well-defined mass is seen on the anterior aspect of the thigh and appears to be mostly isodense relative to the muscle, with curvilinear areas of slightly increased density. The mass appears apposed to the underlying bone.
-
Axial T1-weighted magnetic resonance image of the thigh in a 45-year-old man who presented with a large, right midthigh mass. The anterior mass is well circumscribed, with mostly homogeneous isointensity relative to the muscle. Scattered, small, hyperintense foci probably represent hemorrhage. The fat plane between the mass and the femur is preserved.
-
Coronal T2-weighted magnetic resonance image of the thigh in a 45-year-old man who presented with a large midthigh mass on the right. On this T2-weighted image, the mass has become markedly heterogeneous, with high signal intensity depicting cystic regions of hemorrhage and necrosis. Note that portions of the mass are hyperintense relative to the subcutaneous fat. The location of the mass is somewhat atypical because it is centered at the level of the midshaft rather than near a joint.
-
Sagittal T1-weighted magnetic resonance image of the thigh in a patient with a mass in the anterior left upper thigh and/or inguinal region. The image shows large areas of hemorrhage and necrosis, with intermediate signal intensity on a background of a muscle-intensity mass.
-
Axial T2-weighted magnetic resonance image of the hip in a patient with a mass in the anterior left upper thigh and/or inguinal region. The mass is inseparable from the underlying femoral cortex and contains strikingly hyperintense cystic areas with irregular septa of intermediate signal intensity.
of
12
