Localized type tenosynovial giant cell tumor with metastases to lungs and pleura: a case report and literature review.

Background: Tenosynovial giant cell tumor is a rare soft tissue tumor of the synovium of joint, bursae, or tendon sheath. It is divided into localized or diffuse types on the basis of the growth pattern. Localized tenosynovial giant cell tumors are usually benign and treated successfully by excision. Diffuse tenosynovial giant cell tumors, in contrast to localized type, can destroy bone and cartilage and are associated with frequent local recurrences and distant metastasis. Localized type tenosynovial giant cell tumors rarely metastasize to distant organs. Here, we report a case of localized tenosynovial giant cell tumor presenting with lung metastases and systematically review literature.

Case presentation: A 55-year-old Asian male presented with a dry cough, right-sided chest pain and progressive dyspnea for 1 month. At 18 months before this presentation, he had undergone excision of a painless swelling on his right index finger. The swelling recurred within 3 months of excision, and a biopsy was then suggestive of a giant cell tumor. Given the suspicion of a giant cell tumor, a wide excision of the lesion was performed and the excisional biopsy was consistent with a diagnosis of tenosynovial giant cell tumor, localized type. At admission to our hospital, the patient had tachypnoea and absent breath sounds on the right side. A chest radiograph showed a right-sided pleural effusion with a homogenous opacity in the left mid-zone. A contrast-enhanced computed tomography of the chest and abdomen showed right massive pleural effusion and bilateral multiple lobulated heterogeneously enhancing pleural-based masses with areas of internal calcification. Pleural fluid analysis revealed an exudate with no malignant cells on cytology. A lung biopsy showed osteoclast-like giant cells and mononuclear spindle cells with areas of hemorrhage and necrosis, suggesting tenosynovial giant cell tumor metastasis. A final diagnosis of localized type tenosynovial giant cell tumor of the right index finger with metastases to the lungs and pleura was made. The patient passed away after receiving three cycles of denosumab injection owing to progressive disease.

Conclusion: Lung metastasis is extremely rare in patients with localized tenosynovial giant cell tumor. The survival is usually poor in patients with lung metastasis. A close follow-up of patients with localized type tenosynovial giant cell tumor is necessary for early detection of pleuropulmonary complications.