Are You Confident of the Diagnosis?
Giant cell tumor of the tendon sheath (GCT) is a benign neoplasm that appears to arise from tendon sheath or synovium. It should not be confused with the diffuse type, otherwise known as pigmented villonodular synovitis (PVNS).
What you should be alert for in the history
Volar hand is the most common site (especially the distal interphalangeal [DIP] joint on the second and third digits). GCT may also occur on the dorsum of the hand, wrist, forearm, and toes (less commonly, on the knees, ankles, and elbows). There is a slight predominance for the right hand over the left.
In children, the upper and lower extremities are equally affected, and lesions are less likely to recur following surgery.
Characteristic findings on physical examination
GCT presents as a firm, lobulated, nontender, slow growing fixed mass (Figure 1). Skin is typically adherent in lesions on fingers and hand. Lesions are usually solitary; rare multiple lesions have been described. GCT is generally nontender; occasional mild numbness or dysfunction may occur.
Expected results of diagnostic studies
TYPICAL RADIOGRAPHIC FINDINGS
Typical findings include a benign-appearing well-circumscribed soft-tissue shadow on plain films. Occasionally, there may be cortical erosion of adjacent bone, secondary to the pressure effect of the compressing GCT (this may be mistaken for periosteal chondroma in some cases).
Bone invasion is typically absent; if present, an aggressive neoplasm should be suspected instead. In some cases, intralesional soft tissue calcification may occur, which could be confused with synovial chondromatosis, periosteal chondroma, or calcific tendinitis.
Magnetic resonance imaging often shows decreased signal intensity due to hemosiderin deposition.
Ultrasonography shows a soft mass related to the tendon sheath that is hypervascular on Doppler imaging.
TYPICAL PATHOLOGIC FINDINGS
Typical findings include well-circumscribed multinodular masses, usually 0.5 to 5cm in diameter. Shallow grooves along the deep surface, created by underlying tendons, are common. Lesions on the hands are usually smaller and more regular than those at other anatomic sites.
Cut sections have a mottled pale tan to gray-brown or yellow-orange color, depending on the proportion of hemosiderin, collagen, and neoplastic cells.
Histopathology shows a sharply demarcated cellular lobule, composed of sheets of round, oval, or polygonal mononuclear cells, which blend with hypocellular collagenized areas. Mononuclear cells are admixed with a widely variable number of large osteoclast-like giant cells and macrophages with foamy cytoplasm. Hemosiderin is often present, particularly at the periphery. A capsule of compressed collagen often surrounds the tumor and may form fibrous septa that surround lobules of neoplastic cells.
Clinical differential diagnosis includes fibrokeratoma, myxoid cyst, reticulohistiocytoma, fibromatosis, and rarely, sarcoma, especially epithelioid sarcoma and synovial sarcoma.
Who is at Risk for Developing this Disease?
GCTs are relatively common and are the second most common tumor of the hand (after ganglion cysts). GCT has a predilection for adults aged 30 to 60, with a peak incidence at age 55; it is rarely seen in those younger than 10 or older than 70. There is a female predominance, with a male to female ratio of 2:3.
What is the Cause of the Disease?
The etiology is unknown.
Some cases are associated with degenerative joint disease, particularly in the DIP joint. This can be seen on radiologic review. Rheumatoid arthritis has been associated in some cases, but no proven pathologic relationship exists and their co-occurrence may be incidental. Some patients report prior trauma, but the relationship of GCT to trauma is not established convincingly.
Disturbed lipid metabolism, osteoclast proliferation, infection, immune mechanisms, vascular disturbances, inflammation, neoplasia, and metabolic disturbances have also been proposed causes. The histologic resemblance to osteoclasts suggests a bone marrow monocyte/macrophage line derivation for the neoplastic cell population.
Systemic Implications and Complications
Cortical erosion due to the pressure of the lesion, or mild numbness and dysfunction distal to the lesion, may occur due to compression. GCT may be associated with osteoarthritis, particularly in the DIP joints. Coinciding cases of rheumatoid arthritis have been reported, but are likely incidental.
Complications of excisional surgery may include transient numbness, infection, or loss of function due to dissection of structures with which the tumor is involved.
Marginal excision is the treatment of choice. If the patient is asymptomatic, surgical treatment may not be necessary.
Excision often includes partial excision of the joint capsule or tendon sheath, due to the close association of the tumor to these structures. Subclinical satellite lesions are not uncommon, necessitating careful dissection and exploration.
Seeding of adjacent soft tissue may be possible; this may be avoidable if the lesion is not punctured during excision. If an adjacent bony erosion is present, debridement may be necessary.
If the tumor involves the overlying skin, an elliptical area of skin may be removed with the underlying lesion, and the area then grafted.
If tumor excision compromises the associated tendon, tendon reconstruction may occasionally be necessary.
An alternative is a less aggressive surgery to maintain the underlying structures and function, understanding the increased likelihood for recurrence.
Radiotherapy has been used as an adjuvant to prevent tumor regrowth in patients at high risk for recurrence, with variable success.
Optimal Therapeutic Approach for this Disease
Marginal excision by a hand surgeon is the treatment of choice. GCTs are benign and cost/benefit analysis of surgery should be considered. Rapid growth or regrowth might suggest misdiagnosis; epithelioid sarcomas are occasionally misdiagnosed as giant cell tumors. Patients should be instructed to return for evaluation if there is recurrence.
Recurrence is relatively common, with rates ranging from 9% to 44% (variability likely reflects incomplete excisions and/or unrecognized satellite lesions).
Degenerative joint disease at an adjacent location, histologic atypia, and the radiographic finding of an interosseous erosion are potential risk factors for recurrence. Higher risk for recurrence is conferred by involvement of the extensor tendon, flexor tendon, or joint capsule.
Close follow-up may be warranted for those with risk factors for recurrence, or those patients who have incomplete resection.
Unusual Clinical Scenarios to Consider in Patient Management
Extraordinarily, cases diagnosed as GCT have metastasized; the criteria for malignant GCT are not well-established, and currently there are no well established clinical or histopathologic features that reliably predict metastatic potential.
What is the Evidence?
Altaykan, A, Yildiz, K, Hapa, O, Cukur, S. “Multifocal giant cell tumor of the tendon sheath occurring at different localizations of the same tendon of a finger: a case report and review of the literature”. Eklam Hastalik Cerrahisi. vol. 20. 2009. pp. 119-23. (The authors report a case of GCT in which two separate lesions developed simultaneously on the same tendon.)
Al-Qattan, MM. “Giant cell tumours of the tendon sheath: classification and recurrence rate”. J Hand Surg [Br]. vol. 26. 2001. pp. 72-5. (In this prospective study, the authors classified forty-three cases of GCT by gross inspection intraoperatively, and found increased risk of recurrence with certain gross features and incomplete resections.)
Gholve, PA, Hosalkar, HS, Kreiger, PA, Dormans, JP. “Giant cell tumor of tendon sheath: largest single series in children”. J Pediatr Orthop. vol. 27. 2007. pp. 67-74. (The authors retrospectively reviewed the charts of twenty-nine children diagnosed with GCT over a 16-year period, and followed them by telephone survey for at least 1 to 2 years following surgery to assess recurrence, symptoms, and functionality.)
Goda, JS, Patil, P, Krishnappan, C, Elangovan, D. “Giant cell tumor of the tendon sheath treated by brachytherapy (surface mold) technique – A technical illustration”. Brachytherapy. vol. 8. 2009. pp. 79-83. (The authors developed a brachytherapy mold technique to irradiate a GCT with iridium-192 in an index patient, showing both safety and good functional outcomes while achieving tumor control.)
Shinjo, K, Miyake, N, Takahashi, Y. “Malignant giant cell tumor of the tendon sheath: an autopsy report and review of the literature”. Jpn J Clin Oncol. vol. 23. 1993. pp. 317-24. (The authors report a case and autopsy of a patient with malignant GCT, as well as present a review of the literature containing similar reports of malignant cases.)
Wan, JM, Magarelli, N, Peh, WC, Guglielmi, G, Shek, TW. “Imaging of giant cell tumour of the tendon sheath”. Radiol Med. vol. 115. 2010. pp. 141-51. (The authors review the clinicopathologic features and imaging findings of GCT both in focal and diffuse forms on various imaging techniques.)
Williams, J, Hodari, A, Janevski, P, Siddiqui, A. “Recurrence of giant cell tumors in the hand: a prospective study”. J Hand Surg [Am]. vol. 35. 2010. pp. 451-6. (This prospective study of 213 cases demonstrated a recurrence rate of 13% overall, with tumors involving the extensor tendon, flexor tendon, or joint capsule having the highest risk for recurrence.)
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