History
Giant cell tumors (GCTs) of the tendon sheath are usually painless masses that have been present for a long time. The reported duration of symptoms ranges from weeks to as long as 30 years. These tumors usually cause no symptoms, except for occasional distal numbness; however, mild disability may result from impaired function of the digit secondary to the size of the lesion.
Physical Examination
Typically, these masses occur along the volar aspect of the hand and fingers [28] and are most commonly adjacent to the distal interphalangeal (DIP) joint. [29, 30, 31] Two thirds of these masses are located along the volar aspect of the fingers (see the image below). The index and long fingers are most commonly involved. Despite the prevalence of volar lesions, a dorsal location is not uncommon. A slight predominance for the right hand exists. The second most common site is the toe. Less common sites include extra-articular areas around larger joints, such as the knees, wrists, and ankles. [32]
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.
GCTs of the tendon sheath are firm, lobulated, nontender, slow-growing masses that are firmly fixed to the underlying structures. Usually, the overlying skin is freely mobile over proximal masses in the fingers. The skin is adherent to distal tumors. In digital lesions, mild numbness in the distal part of the involved fingertip is occasionally present. The lesion is not transilluminating. (Transillumination is more consistent with a cystic structure.)
The clinical differential diagnosis may include foreign body granuloma, necrobiotic granuloma, tendinous xanthoma, [33] fibroma of the tendon sheath, infection, ganglion cyst, rheumatoid nodule, epidermoid cyst, lipoma, and a knuckle pad, among other less common entities. Many of these entities can often be excluded with careful history taking and physical examination.
When the pressure of the mass causes cortical erosion or when the mass has intralesional calcification, the radiographic differential diagnosis includes synovial chondromatosis, calcific tendinitis, and periosteal chondroma. Other entities that cannot be excluded on the basis of clinical findings in many cases include fibrokeratoma, myxoid cyst, reticulohistiocytoma, metastasis, and soft-tissue sarcomas (particularly epithelioid sarcoma and synovial sarcoma); these entities can only be definitively distinguished by means of histologic review.
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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.
