Tendon sheath fibromas are rare proliferative lesions with common imaging features of tenosynovial giant cell tumors.
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Epidemiology
They are found in adults typically between the age of 20 and 50 with a 3:1 male predominance 2.
Pathology
Tendon sheath fibromas are lobulated, round-to-oval, encapsulated masses consisting of spindle cells and collagen fibers that arise from the synovium of a tendon sheath 1,2.
Location
Tendon sheath fibromas can arise around 2,3:
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small joints
finger (~50%)
hand (~25%): most commonly the flexor surface
wrist (~10%)
large joints (~5%): knee, shoulder, elbow and ankle
They can be intra-articular or extra-articular 2.
Radiographic features
MRI
T1: low-to-iso signal
T2: heterogeneous
GRE: absent susceptibility artifact
T1 C+ (Gd): no or variable contrast enhancement
Treatment and prognosis
Treatment is usually surgical excision. There is a very low recurrence rate and these tumors are not reported to have undergone malignant transformation 3.
Differential diagnosis
tenosynovial giant cell tumor: will often show susceptibility artifact on GRE 1
