Practice Essentials
Giant cell tumors (GCTs) of the tendon sheath are the second most common tumors of the hand, with simple ganglion cysts being the most common. [1] Chassaignac first described these benign soft-tissue masses in 1852, and he overstated their biologic potential in referring to them as cancers of the tendon sheath.
GCTs of soft tissue are classified into the following two types:
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Localized (common)
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Diffuse (rare)
The rare diffuse form is considered the soft-tissue counterpart of diffuse pigmented villonodular synovitis (PVNS) and typically affects the lower extremities. [2] Its anatomic distribution parallels that of PVNS, with lesions most commonly found around the knee, followed by the ankle and foot; however, it occasionally affects the hand. Typically, these lesions, like those of PVNS, occur in young patients; 50% of cases are diagnosed in patients younger than 40 years. The diffuse form is often locally aggressive, and multiple recurrences after excision are common.
Because of the similarities in age, tumor locations, clinical presentations, and symptoms for patients with PVNS and patients with the diffuse form of GCTs of the tendon sheath, the diffuse form probably represents an extra-articular extension of a primary intra-articular PVNS process.
Findings from flow cytometric DNA analysis have suggested that PVNS and giant cell tumors of the tendon sheath are histopathologically similar but clinically distinct lesions. [3] When the origin of these poorly confined soft-tissue masses is uncertain, the tumors have been classified as the diffuse type of GCTs of the tendon sheath, [4] whether or not they involve the adjacent joint. [5]
GCTs of the tendon sheath are usually painless masses that have been present for a long time. Although they typically cause no symptoms, aside from occasional distal numbness, mild disability may result if the lesion impairs the functioning of the digit.
Marginal excision of has typically been the treatment of choice for these lesions; however, systemic pharmacotherapy (pexidartinib) is available. Contraindications for surgical resection include poor patient health and the presence of a life-threatening illness.
This article focuses on the common localized form of GCTs—that is, the GCTs of the tendon sheath that are often found in the hands and feet. [6, 7, 8, 9, 10]
Etiology
As is true for most soft-tissue tumors, the etiology of GCTs of the tendon sheath is unknown. Pathogenetic theories have included trauma, disturbed lipid metabolism, osteoclastic proliferation, infection, vascular disturbances, immune mechanisms, inflammation, neoplasia, and metabolic disturbances. [11] Probably the most widely accepted theory is that of a reactive or regenerative hyperplasia associated with an inflammatory process.
Histochemical evidence has shown that the mononuclear cells and giant cells present in these lesions resemble osteoclasts, [12] and this resemblance suggests a bone marrow–derived monocyte/macrophage lineage for these tumors. Polymerase chain reaction (PCR) assays have shown that GCTs of the tendon sheath are polyclonal proliferations, [13] which suggests that these masses are nonneoplastic proliferations, if one accepts the premise that a population of cells forming a tumorous mass must show clonality to be classified as a neoplasm.
Epidemiology
GCTs of the tendon sheath are the second most common tumors in the hand; simple ganglion cysts are the most common. GCTs of the tendon sheath most commonly occur in patients aged 30-50 years, with a peak incidence in those aged 40-50 years. Rarely are these tumors found in patients younger than 10 years or older than 60 years. The female-to-male ratio is 3:2.
GCTs of the tendon sheath are associated with degenerative joint disease (DJD), especially in the distal interphalangeal (DIP) joint. Jones et al [14] noted DJD in the joint from which a tumor arose or in the joint nearest to the mass in 46 of 91 cases in which radiographs were reviewed.
An occasional association with rheumatoid arthritis (RA) has been reported; however, to the authors' knowledge, no pathogenetic relation between RA and GCT of the tendon sheath has been demonstrated, and their simultaneous occurrence may be coincidental. Antecedent trauma occurs in a variable number of these patients, but its association with these tumors is also probably coincidental.
Prognosis
The incidence of local recurrence is high, ranging from 9% to 44%. The variability in rates probably reflects incomplete excision of the lesions, especially the satellite nodules. Risk factors for recurrence include the following:
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Presence of adjacent DJD
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Injury at the DIP joint of the finger or the interphalangeal (IP) joint of the thumb
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Radiographic presence of osseous pressure erosions
Goda et al have presented a new technique for the use of radiotherapy as an adjuvant modality to prevent local recurrence. [15] For retrospective studies, see Rodrigues et al, [16] Darwish and Haddad, [17] and Messoudi et al. [18] For a significant study in children, see Gholve et al. [19]
To the authors' knowledge, no cases of malignant degeneration of a benign GCT of the tendon sheath of the hand have been reported. These tumors also have no propensity to metastasize distally. A few sporadic cases of purported malignant GCTs have been reported; however, most authors doubt that these malignant tumors exist, because this diagnosis is difficult to confirm.
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Image in a 44-year-old right hand–dominant man who presented with a mass on the volar radial aspect of his left index finger. The mass was painless and had been slowly growing for 1.5 years.
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Radiograph demonstrates cortical erosion from the pressure effect of the adjacent mass on the radial aspect of the proximal phalanx.
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Radiograph demonstrates the bony erosion associated with some giant cell tumors of the tendon sheath and shows the unmineralized soft-tissue shadow of the mass.
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Radiograph demonstrates cortical erosion from the pressure effect of the overlying giant cell tumor of the tendon sheath. This apple-core effect is indicative of a primary soft-tissue mass that is causing external erosion, which should not be confused with a primary bone process such as periosteal chondroma.
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Radiograph demonstrates cortical erosion from the pressure effect of the overlying giant cell tumor of the tendon sheath.
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Histologic findings of a giant cell tumor of the tendon sheath.
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High-power photomicrograph depicts the histologic findings of a giant cell tumor of the tendon sheath.
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Typical T2-weighted MRI appearance of a giant cell tumor of the tendon sheath. Most of the tumor has intermediate signal intensity, and portions of the tumor have low signal intensity; the latter finding likely reflects signal attenuation due to hemosiderin deposition.
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Typical T1-weighted MRI appearance of a giant cell tumor of the tendon sheath. Portions of the tumor have decreased signal intensity.
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Typical T1-weighted MRI findings in a giant cell tumor of the tendon sheath overlying the metacarpophalangeal joint. Note the low-signal-intensity areas.
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Corresponding T2-weighted MRI findings in the tumor shown in the image above. Note the areas of low signal intensity.
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Intraoperative excision of the giant cell tumor of the tendon sheath, which has the typical golden-yellow color secondary to hemosiderin deposition. The radial digital nerve is dissected free and slightly volar to the mass.
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After excision, the bone is curetted, leaving the exposed radial aspect of the proximal phalanx, as shown here.
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Giant cell tumor of the tendon sheath after marginal excision.
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Typical microscopic appearance of a giant cell tumor of the tendon sheath. Sheets of rounded or polygonal cells blend with hypocellular collagenized zones; variable numbers of giant cells are present.
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High-power photomicrograph of giant cell tumor of the tendon sheath shows occasional numerous mononuclear cells, scattered giant cells, and hemosiderin-containing xanthoma cells.
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An 11-year-old girl presented with this firm nonfluctuant mass over her posterior medial left ankle that had been present for 5 months and had not increased in size. The mass was not transilluminating. Findings on frozen section were consistent with a benign giant cell tumor of the tendon sheath. The mass was marginally excised.
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Giant cell tumor of the tendon sheath after marginal excision from an 11-year-old girl who presented with a firm nonfluctuant mass over her posterior medial left ankle that had been present for 5 months and had not increased in size.
