50-year-old woman, not suffering from a chronic pathology but having previously undergone surgery for a benign right parotid adenoma; comes to my attention for tense elastic swellings affecting the 1st and 2nd ray of the right hand which arose approximately 12 months ago, progressively growing and painful on palpation. The result of the ultrasound is the following:
“The ultrasound study of the right hand shows how the palpable swellings at the level of the 1st and 2nd ray correspond to solid, hypoechoic and non-homogeneous dermal nodules, essentially cleavable margins, not in direct continuity with the underlying joints; in particular, the nodule of the II radius, approximately 14.5x5mm, is positioned above the extensor tendon and the IFP without causing an excessive limit to its sliding during dynamic maneuvers. A similar formation is also noted on the dermis of the 2nd phalanx, again on the 1st right ray, and on the internal side of the IFP (well cleavable because it is at a safe distance from the tendon structures). Thickening of the subcutaneous tissue with similar reduced echogenicity but with poorly definable margins is also identified at the level of the third left ray in correspondence with the IFP joint. All the nodules analyzed do not show the presence of significant internal vascular signals, even on the Doppler study of the microcirculation. The arthritic erosions of the bone boundaries analyzed were modest, however more evident at the MCF level. No associated joint effusions. The picture described is compatible in the first instance with giant cell tumor (TGC) type hypodermic nodules of presumably capsular origin, as the nodules are mainly located above the joints of the hands without significantly limiting their movement. tendon. Useful surgical re-evaluation".
I therefore invite the patient to carry out a level II diagnostic investigation despite the apparent ultrasound benignity of the formation, in particular an MRI of the soft tissues with contrast medium, which however she prefers not to carry out. The patient returns to me after about 15 months due to persistence and increase in size of the swelling; on ultrasound examination the nodule of the second radius of the right hand in particular reaches a total size of 21x7mm.
I therefore invite the patient to go to her orthopedist for an evaluation of the surgical excision of the lesion. The patient underwent surgery at the Orthopedic Trauma Center of Florence (C.T.O.) with complete removal of the formation and subsequent histological diagnosis of TENOSYNOVIAL GIANT CELL TUMOR (TGCT), an essentially benign tumor that originates from the synovial sheaths of the tendons. The patient is currently undergoing a six-monthly ultrasound follow-up.
Tenosynovial giant cell tumor (TGCT), previously called pigmented villonodular synovitis (PVNS), nodular synovitis, and/or giant cell tendon sheath tumor (GCT-TS), is a rare soft tissue tumor that arises from the joint (synovium) and the tissue surrounding the tendons (tendon sheath). The tissue is often colored due to hemosiderin. Hemosiderin is an iron-storing compound that leads to rust-colored, yellow, red, and orange pigmentation. This pigmentation gave rise to the initial name of PVNS. TGCT is characterized by a genetic abnormality that causes the abnormal production of a protein called colony-stimulating factor 1 (CSF1). The increase in CSF1 protein is a result of a genetic abnormality that is present in approximately 2-16% of tumor cells. The 2020 WHO Classification of Sarcomas of Soft Tissue and Bone defines TGCT as a locally aggressive tumor disease. Sarcomatous TGCT, which spreads to other organs, is extremely rare. Most patients with TGCT are young, and while TGCT is not usually life-threatening, the disease and its treatment can affect quality of life
The definition of TGCT includes two distinct subgroups, N-TGCT (nodular) and diffuse D-TGCT). N-TGCT corresponds to localized disease and the name “nodular” accurately describes its behavior. The term "nodular" better reflects the appearance of these lesions on radiological imaging, often with a rounded shape, and the clinical behavior. N-TGCT typically manifests itself as a single lesion, which slowly evolves over many years. These forms grow, taking up space in the soft tissues, near the tendons and joints of the phalanges, particularly in the fingers and toes in most cases. Occasionally N-TGCT can erode bone or damage other parts of the limb, such as the skin layer. Large joints are less frequently involved by N-TGCT. In contrast, diffuse TGCT (D-TGCT) shows extensive and infiltrative involvement of the joint and/or tendon sheath and may extend outside the joint. D-TGCT can cause joint hemorrhages, destruction of bone and cartilage causing severe disability and frequent relapses. TGCT can substantially change the patient's quality of life, however, it is rarely lethal. An exception is malignant TGCT (M-TGCT), also known as the cancerous form of TGCT, which can arise from the beginning or following multiple relapses. This is an exceptionally rare and controversial event.
N- and D-TGCT are more common in women than in men. The average age at diagnosis is 35-50 years, with slight differences in gender and subtype. TGCT can involve any joint. However, most N-TGCTs affect the hands and wrist followed less often by the knee, while most D-TGCTs affect the knee, ankle and hip). N-TGCT of the elbow is extremely rare. Relapses are lower in N-TGCT (9-14%) than in D-TGCT (23-72). The 5-year recurrence rate for N-TGCT is 10-30% and 20-70% for D- TGCT. Information on the frequency of TGCT in children is scarce.
Major radiological diagnoses that resemble N-TGCT in the hands and feet include:
- fibroma of the tendon sheath
- ganglion cyst
- hemangioma
- angiomyoma
- bizarre osteochondromatous proliferation (BPOP, Nora lesion)
- topical gout
The main considerations to make in determining whether or not a patient is affected by TGCT include testing for hemosiderin. For intra-articular N-TGCTs of the extremities, such as the knee, the main differential diagnoses with N-TGCT include:
synovial chondroma (which can be excluded with some MRI techniques and comparison with X-rays to determine the presence of minerals in the mass).
Extra-articular D-TGCT may look like imaging at:
- synovial osteochondromatosis (SOC)
- rheumatic disease
- chronic non-specific synovitis
- haemophilic arthropathy (joint damage due to blood diseases).
Taken from the document:
“Clinical management of tenosynovial giant cell tumor (TGCT): expert community consensus document”
Sydney Stern, Amy Hall, Sebastian Bauer, Silvia Stacchiotti, Giacomo Giulio Baldi, Sara Rothschild und Kathrin Schuster