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Giant Cell Tumor of Tendon Sheath


Giant cell tumor of tendon sheath is a rare, solitary benign soft tissue tumor which may arise in the tendon sheath tissues of the hand and wrist as well as the ankle and foot. Most cases occur in the hand, where local recurrence after excision has been reported in up to 40% of cases. Approximately 3 - 10% of these tumors occur in the foot, most commonly in the forefoot, especially the great toe. ((Ushijima) Most patients are young adults, around age 30.

Clinically, the patients report a slow growing painless, firm solitary mass adjacent to the dorsal or plantar tendons, the midfoot joints, or the ankle joint, which has been present for one to two years on average. There may be a history of trauma, and neurological symptoms occur rarely. In one study, lesions in the forefoot occurred in the first, second, and fifth rays exclusively, indicating that there may be some relationship between weight-bearing and this tumor. The tumor may cause or accentuate an angular deformity such as hallux valgus.

Complete Information on this Tumor
X-Ray Appearance and Advanced Imaging Findings: 
On plain radiographs, there may be a visible soft tissue swelling, sometimes completely encasing the bony elements of the involved digit, and the tumor may invade the adjacent bone and cause cystic lesions that are clearly visible on xray. Approximately 10% involve bone. The bone involvement and destruction leads to concern for primary bone malignancy, and inappropriately aggressive treatments can result. CT scan will show the extent of the tumor, and clearly delineate any bony involvement. Some of these tumors have small calcifications, feature shared with synovial sarcoma. MRI scans are helpful to define the extent of the lesion, and can be helpful in the preoperative diagnosis. Hemosiderin in the lesion may result in vary low signal intensities on some sequences, and the lesions enhance on T1 sequences after administration of gadopentetate contrast agent, and these features help identify the tumor. Histologically, the lesion is similar to pigmented villonodular synovitis. There is hemosiderin and frequent macrophages, foam cells, and giant multi-nucleated cells. The origin of the tumor is unclear. DNA aneuploidy, chromosomal translocations, and tumor expression of p63 and nm23 have been reported in a variable proportion of cases. Expression of p63, has been identified in giant cell tumor of bone, pigmented villonodular synovitis, and the giant cell tumor of tendon sheath, leading to speculation that these may share a common origin. The giant cells in all 3 of these tumors have been found to demonstrate features that are associated with osteoclast, including tartrate- resistant acid phosphatase marking, and calcitonin receptor expression.
Differential Diagnosis: 
Based on the location, age, and invasiveness of the tumor, the differential diagnosis may include a large number of benign and malignant lesions, including synovial sarcoma, chondromyxoid fibroma, enchondroma and chondrosarcoma, giant cell tumor, and pigmented villonodular synovitis. Due to be overlapped between the clinical and radiological features of this tumor and that of certain sarcomas, healthcare providers that are not tumor specialist should take great care in managing patient's home they suspect have giant cell tumor of tendon sheath.
Histopathology findings: 
A separate, staged biopsy is strongly recommended. The lesion cannot always be characterized by the preoperative studies, and aggressive or destructive features may be present that are also consistent with malignancy. Open surgical biopsy with frozen section analysis is preferred, performed through a well planned longitudinal incision that avoids any involvement of nearby neurovascular structures. If the lesion can be characterized by MRI, and the level of confidence in the preoperative diagnosis is very high, then excisional biopsy is appropriate.
Treatment Options for this Tumor: 
Treatment is by complete, meticulous excision of the entire lesion. A wide a radical margin is not necessary. Intralesional margins are acceptable, as long as complete excision is not compromised. Recurrence has been reported in up to 45% of cases, but with careful removal, recurrence can be reduced to 10 to 20%. In the lesser toes, where the lesion has extensively invaded the soft tissues and bone, amputation may be preferable to excision. In the great toe, efforts should be made to preserve the mechanical integrity of the first ray, including complete meticulous excision of the lesion, followed by bone grafts, skin grafts, and fusions as necessary.