Diffuse-Type Tenosynovial Giant Cell Tumor: What Are the Important Findings on the Initial and Follow-Up MRI?

Abstract

Tenosynovial giant cell tumor (TSGCT) is a rare soft tissue tumor that involves the synovial lining of joints, bursae, and tendon sheaths, primarily affecting young patients (usually in the fourth decade of life). The tumor comprises two subtypes: the localized type (L-TSGCT) and the diffuse type (D-TSGCT). Although these subtypes share histological and genetic similarities, they present a different prognosis. D-TSGCT tends to exhibit local aggressiveness and a higher recurrence rate compared to L-TSGCT. Magnetic resonance imaging (MRI) is the preferred diagnostic tool for both the initial diagnosis and for treatment planning. When interpreting the initial MRI of a suspected TSGCT, it is essential to consider: (i) the characteristic findings of TSGCT-evident as low to intermediate signal intensity on both T1- and T2-weighted images, with a blooming artifact on gradient-echo sequences due to hemosiderin deposition; (ii) the possibility of D-TSGCT-extensive involvement of the synovial membrane with infiltrative margin; and (iii) the resectability and extent-if resectable, synovectomy is performed; if not, a novel systemic therapy involving colony-stimulating factor 1 receptor inhibitors is administered. In the interpretation of follow-up MRIs of D-TSGCTs after treatment, it is crucial to consider both tumor recurrence and potential complications such as osteoarthritis after surgery as well as the treatment response after systemic treatment. Given its prevalence in young adult patents and significant impact on patients' quality of life, clinical trials exploring new agents targeting D-TSGCT are currently underway. Consequently, understanding the characteristic MRI findings of D-TSGCT before and after treatment is imperative.

Keywords: diffuse type; local recurrence; magnetic resonance imaging; osteoarthritis; targeted therapy; tenosynovial giant cell tumor; treatment response.

Figure 1

A 46-year-old female with D-TSGCT in the knee. (A) Axial T1WI shows iso-to-low SI mass (arrow). (B) Axial fat-suppressed T2WI shows heterogeneously high SI (arrow). (C,D) Sagittal fat-suppressed T2WI images show nodular thickening of synovium containing low SI foci (arrows) with extra-articular extension (arrowheads). (E,F) Sagittal GRE sequences show blooming artifact due to hemosiderin deposition along the synovium (arrowheads).

Figure 2

Enhancement patterns of pathology-proven D-TSCGT. (A) No contrast enhancement within the lobulated mass (arrowheads) in the posterior knee. (B) Peripheral contrast enhancement of the mass with a sparing central portion (arrowheads) in the posterior knee. (C) Heterogenous contrast enhancement of the mass (arrowheads) in the posterior ankle. (D) Homogenous contrast enhancement of the mass (arrowheads) surrounding the third metacarpal bone.

Figure 3

A 27-year-old female with D-TSGCT in the knee. (A) Sagittal T2WI shows diffuse and multinodular synovial thickening with scattered dark SI foci (arrows) in the knee joint space. Extra-articular extension to the popliteus myotendinous junction is noted (arrowhead). (B,C) Coronal and axial fat-suppressed T2WIs show that proliferated synovium engulfs the reactive joint effusion resulting in multichambered cystic mass-like lesions around popliteal fossa (arrowheads). (D) Axial contrast-enhanced T1WI reveals thickened synovium as diffuse septal enhancement within the cystic changes (arrowheads).

Figure 4

A 40-year-old female with D-TSGCT in the tibia. (A) Coronal GRE sequence shows a lobulated heterogenous SI mass in the juxtacortical area of the proximal metaphysis of the tibia with blooming artifact (arrow). Note that there is no remarkable intra-articular communication of the knee joint. (B) Axial fat-suppressed T2WI, (C) T1WI, and (D) fat-suppressed enhanced T1WI show the mass arising from the Pes anserine bursa with focal bony erosion of the adjacent tibia (arrowheads) and infiltration to the adjacent muscle and subcutaneous fat layer (asterisks).

Figure 5

Nodularity, margin, and peripheral hypointensity between two subtypes. (A) Pathology-proven L-TSGCT of the foot shows that the mass is shown as a single mass with a circumscribed margin (arrows) on axial T2WI. The mass shows the avid peripheral hypointensity (see in box) and encasement of the extensor tendon (arrowhead). (B) Pathology-proven D-TSGCT of the foot shows that the masses contain multiple distinct nodules with an infiltrative margin from the surrounding tissues (arrows) on axial T2WI. The masses show the absent peripheral hypointensity (see box) and encasement of the flexor tendon (arrowhead). Box; b = bone, yellow line = tendon.

Figure 6

Involvement of adjacent structures of D-TSGCT on contrast-enhanced fat-suppressed T1WIs. (A) Articular involvement (arrows) of the metatarsophalangeal joint of the foot, also correlated on a plain radiograph (arrowheads) presenting as a periarticular bony change. (B) Bone erosion (asterisk) of the tibia, also correlated on a plain radiograph (arrow). (C) Tendon (arrowhead) and muscular involvement (arrow) with infiltration into the extensor tendon fibers and interosseous muscle of the foot. (D) Neurovascular bundle involvement (arrowheads) with more than 180° encasement of the neurovascular bundle of the foot.

Figure 7

A 29-year-old female with D-TSGCT in the distal femur. (A,B) Sagittal and axial fat-suppressed T2WIs show a low SI mass at the popliteal fossa (arrowheads). (C) Axial T1WI also shows low SI due to extensive hemosiderin deposition (arrowhead). (D,E) The mass shows low SI on low and high b-value images of DWI due to hemosiderin deposition (arrows). (F) The mass creates a pseudo-low ADC value on the ADC map (arrow), suggesting T2 black-out effect.

Figure 8

A 46-year-old male with D-TSGCT in the foot. (A) Axial fat-suppressed T2WI shows a heterogeneously high (asterisk) to low SI soft tissue mass involving the second web space. The mass extends to the plantar muscles. (B) Axial T1WI shows the mass with iso (asterisk) to low SI. (C) Axial contrast-enhanced fat-suppressed T1WI shows the heterogenous enhancement (asterisk) within the mass. (D,E) The enhancing portion of the mass shows persistent high SI on both the low and high b-value images of the DWI (arrowhead). (F) The mass shows a low ADC value (arrowhead) in this area, suggesting diffusion restriction.

Figure 9

A 37-year-old female with D-TSGCT in the hand. (A) Axial fat-suppressed T2WI shows lobulated soft tissue with heterogenous SI around the third MCP joint (arrowhead). (B) Axial T1WI shows the mass with iso SI (arrowhead) and marked extrinsic bony erosion at the metacarpal bone (arrow) is noted. (C) Axial contrast-enhanced fat-suppressed T1WI shows the homogeneous enhancement of the mass (arrowhead). (D,E) Due to microcapillary perfusion, the mass shows an apparent high SI on the low b-value image of the DWI (arrowhead) compared to the high b-value image of the DWI. (F) The mass shows a low ADC value (arrowhead), suggesting diffusion restriction.

Figure 10

A 67-year-old female with hemosiderotic synovitis in the knee. (A) Sagittal fat-suppressed T2WI shows a large amount of joint effusion in the suprapatellar recess (arrowheads). The synovium is diffusely thickened with a dark SI lining (hemosiderin deposition, arrows). (B) Sagittal contrast-enhanced fat-suppressed T1WI shows poor contrast enhancement on the distended suprapatellar bursa (arrowheads).

Figure 11

A 54-year-old male with synovial chondromatosis in the foot. (A) Coronal T2WI demonstrates diffusely low SI of synovial thickening at the Lisfranc or Chopart joints (arrowheads). (B) Axial fat-suppressed T2WI reveals infiltrative soft-tissue extension into the surrounding bone and muscles (arrowheads). (C) Axial contrast-enhanced fat-suppressed T1WI shows minimal peripheral enhancement (arrowheads). (D) Axial CT reveals multiple small conglomerated calcifications in involved tarsometatarsal joints (arrows) with bony erosion.

Figure 12

A 62-year-old female with amyloid arthropathy in both hip joints. (A) Coronal T2WI shows periarticular soft tissue masses (asterisks) extending to intra-articular space with heterogeneously low SI in both hip joints. Bony erosions at both femoral heads (arrows) are combined. (B) Sagittal T2WI shows that the mass infiltrates into the adjacent tendon and muscles (arrowheads).

Figure 13

A 60-year-old female with rheumatoid arthritis of the shoulder. (A) Coronal T2WI demonstrates cystic and erosive change in the glenoid rim (arrowhead) with extensive synovial proliferation in the glenohumeral joint (arrows). (B) Coronal fat-suppressed T2WI shows multiple tiny low SI foci, known as ‘rice bodies’, within the hyperplastic synovium (arrow).

Figure 14

A 39-year-old male with tophaceous gout of the knee. (A) Sagittal T2WI shows heterogeneously low SI masses along the synovial lining of the knee joint (arrows). (B) Sagittal contrast-enhanced fat-suppressed T1WI shows the abnormal enhancement with nodular thickening of patellar tendon (arrowheads). (C,D) Dual-energy CT reveals MSU crystal deposition (asterisks) with green color coding along the synovial linings and quadriceps-patellar aponeurosis. Trabecular or cancellous bone is displayed in purple.

Figure 15

A 44-year-old male with FTS of the knee. (A,B) Axial fat-suppressed T2WI and sagittal T2WI show a well-defined high-SI mass containing strip-like low SI bundles at the popliteal fossa (arrows). (C) Sagittal contrast-enhanced fat-suppressed T1WI shows an ovoid-shaped mass with septal enhancement (arrowhead).

Figure 16

A 40-year-old female with extra-abdominal DF in the lower leg. (A) Axial fat-suppressed T2WI shows a slightly hyperintense intramuscular mass with intralesional dark SI portions (asterisks) in the medial head of the gastrocnemius muscle. (B) Sagittal T2WI shows this lesion with a lobulated contour with an infiltrative margin (arrowheads). (C,D) Sagittal contrast-enhanced fat-suppressed T1WIs show that this mass displays heterogenous enhancement and finger-like tumor extension into adjacent muscle (termed as “staghorn sign”, arrows) and a tapering appearance of the tumor extension along the fascia (termed as “fascial tail sign”, arrowhead).

Figure 17

A 47-year-old male with tophaceous gout of the knee. (A) Axial fat-suppressed T2WI reveals a lobulated extra-articular slightly hyperintense soft tissue mass containing low SI foci along the Pes anserine bursa (arrow). (B) Axial contrast-enhanced fat-suppressed T1WI shows heterogeneous enhancement and focal cortical erosion (arrowhead) at the proximal medial tibia. (C) Dual-energy CT reveals the lesion is tophi with MSU deposition of green color coding (asterisk). Trabecular or cancellous bone is displayed in purple.

Figure 18

Serial T2WI follow-ups for D-TSGCT. (A) Initial MRI shows a low SI mass at the popliteal fossa (arrowhead). (B) After En bloc excision, the first follow-up MRI (1 year) shows small low SI nodule at the posterior joint capsule (arrowhead). (C) Second follow-up MRI (3 years) shows recurrent mass extra-articularly (arrowhead) and extensive nodular thickening intra-articularly (arrow).

Figure 19

A 47-year-old male with D-TSGCT in the right hip joint. (A) Initial coronal fat-suppressed T2WI shows a tiny low SI nodular synovial thickening in the right hip joint (arrowheads). (B) After synovectomy, follow-up CT after 4 years shows the development of osteoarthritis (arrows) in the right hip joint.