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© 1996 The Journal of Bone and Joint Surgery, Inc. Benign Giant-Cell Tumor of Bone with Metastasis to Mediastinal Lymph Nodes. A Case Report of Resection Facilitated with Use of steroids* , NEW YORK, N.Y.Investigation performed at Memorial Sloan-Kettering Cancer Center and Cornell University Medical College, New York City
Benign giant-cell tumor of bone is an aggressive lesion that behaves in an unpredictable fashion. These benign tumors often recur locally and, although it is rare, may even metastasize. The frequency of metastases is approximately 2 to 3 per cent12,19. Most metastases are to the lung; metastases to other sites, including the regional lymph nodes, the scalp, and the pelvis, are extremely rare. This report describes a patient who was referred to our institution because of a local recurrence of benign giant-cell tumor that was later complicated by metastasis to the mediastinal lymph nodes.
A fifty-nine-year-old man was first seen at another institution in March 1986. He reported that he had had pain in the right wrist for five months. Radiographic evaluation revealed a large, well delineated, lucent tumor of the distal part of the radius that was consistent with a diagnosis of benign giant-cell tumor. The patient was taken to the operating room, where excision of the tumor by curettage followed by iliac bone-grafting was performed. In December 1986, a local recurrence developed and the patient was referred to our institution. Wide en bloc resection of the right radius was performed, and an arthrodesis of the wrist was done with an intercalary fibular graft. In May 1992, the patient sustained a comminuted fracture of the fibular graft that caused malalignment of the wrist and was complicated by non-union. The fracture was treated with open reduction and internal fixation as well as bone-grafting. Histopathological evaluation of multiple biopsy specimens revealed no evidence of local recurrence of the tumor. At that time, a radiograph of the chest demonstrated a large mediastinal mass. A computed tomography scan of the chest (Fig. 1-A) revealed a mass that measured 8.5 by 5.5 by 10.0 centimeters in the cephalad part of the anterior mediastinum. The mass extended from the left innominate vein down to the left ventricle and compressed the superior vena cava. There was no evidence on the computed tomography scan of any pulmonary metastases, and the mediastinal mass appeared to be separate from the adjacent right lung.
In June 1992, bronchoscopy and an anterior mediastinotomy on the right was performed. A biopsy of the mass was done, and it confirmed the diagnosis of metastatic benign giant-cell tumor of bone in the lymph nodes, which was histologically identical (Figs. 2-A, 2-B, and Fig. 2-C) to the primary tumor.
Because of the large size of the metastatic mediastinal tumor and the proximity to vital mediastinal structures, it was decided to attempt to reduce the size of the tumor with high doses of corticosteroids. The patient was started on a titrated initial dose of twenty milligrams of prednisone together with prophylactic administration of Tagamet (cimetidine) and Bactrim (trimethoprim and sulfamethoxazole). A computed tomography scan (Fig. 1-B) made five months later showed a reduction in the size of the mass of approximately 66 per cent.
The dosage of prednisone was tapered to five milligrams per day for a two-week period, and a median sternotomy with resection of the mediastinal mass was performed in November 1992. This was accomplished by dissection of the tumor off the pericardium and superior vena cava, and it included en bloc resection of a small wedge of the right upper lobe adherent to the tumor. Although the tumor was adherent to the visceral pleura of the lung, there was no evidence of any primary or secondary involvement of the lung. The patient had an uneventful postoperative recovery, and use of the prednisone was tapered off during the next two weeks. The findings of the pathological examination of the resected specimen were again consistent with a histologically benign giant-cell tumor and were similar to those of the biopsy of the mediastinal mass before the use of prednisone. At the most recent follow-up visit, in July 1994 (nineteen months after the operative resection), the patient had no evidence of disease.
There have been numerous reports of benign giant-cell tumors of bone metastasizing to the lung1,4,5,7,9-17,19,22,23. The prevalence of pulmonary metastases is estimated to be approximately 2 to 3 per cent12,19. The histological appearance of the metastasis is usually the same as that of the primary tumor, with no evidence of malignant change in the interval. Although most reported metastases of benign giant-cell tumor have been to the lungs, solitary metastases to other sites, including the regional lymph nodes17, the scalp, and the pelvis18, have been described. We know of two reports of involvement of the mediastinal lymph nodes in association with pulmonary metastases18,21. In contrast, our patient had metastasis to the mediastinal lymph nodes as the only manifestation of metastatic disease. The treatment of benign giant-cell tumor of bone has been complicated by a rate of local recurrence as high as 50 per cent6, the late development of malignant change in nineteen (4 per cent) of more than 400 patients20, and the development of metastases in seven (3 per cent) of 265 patients in one series12 and eight (2 per cent) of 400 patients in another19. Although local recurrences are often related to the inadequacy of primary treatment, and secondary malignant change may follow radiation therapy, the development of metastases is unpredictable6. The biological mechanism of metastasis of benign giant-cell tumor is uncertain. Microvascular trauma resulting in tumor embolization at the time of curettage can be implicated in most patients, although it cannot account for metastasis occurring before an operation3. Clearly, because the prevalence of tumor microemboli at the time of curettage must be greater than the prevalence of metastases, other biological factors, including immune surveillance and the intrinsic biological characterics of the tumor, must be operative. The natural history of metastasic lesions may be unpredictable. They typically progress, although some ossify peripherally and remain dormant. Although it is rare, metastatic lesions of the lung have disappeared after biopsy only3. Complete excision of pulmonary nodules is frequently curative, whereas patients who have inoperable disease may die from metastases2-4,6,19. Both radiation and chemotherapy have had only limited success3,19. Consequently, a metastatic lesion should, if at all possible, be resected. Steroids were used as the initial therapy for the unresectable metastasis in our patient because of a report of a giant-cell tumor in Paget disease that had responded to steroids8 and because of our experience with steroids inducing regression of tumors containing giant cells. To our knowledge, this is the first report of conventional giant-cell tumor of bone responding to steroids. The mechanism of steroid-induced regression of giant-cell tumor is unknown. We agree with the conclusions of others19 that patients who have been managed for benign giant-cell tumor of bone should be followed at frequent intervals (every three to six months), with radiographs of the chest in conjunction with monitoring for local recurrence. A metastasis should be treated with operative resection. If it is unresectable, therapy with high doses of steroids may facilitate resection by reducing the size of the tumor.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
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