Detection of pulmonary metastases in a patient with synovial cell sarcoma using In-111 labeled monoclonal antibody...

A 35-year-old man was diagnosed in 1984 as having a synovial cell sarcoma of his right wrist without evidence of metastatic spread. The patient underwent regional hyperthermic chemoperfusion, wide-field excision, post-operative radiation therapy and systemic adjuvant chemotherapy. In 1986 and in 1987, because of new lesions found on chest radiographs, the patient underwent bilateral staging thoracotomies with resection of pulmonary metastases, followed by chemotherapy and radiotherapy. Later in 1987, a chest radiograph showed a large left hilar mass and multiple bilateral pulmonary nodules. Computerized tomography of the chest demonstrated a left hilar mass and two nodules in the right lower lung, raising the possibility of recurrent pulmonary metastatic cancer. As a diagnostic procedure, In-111 labeled monoclonal antibody (Mab) 19-24, produced against a human malignant fibrous histiocytoma, was infused intravenously, and 48-hour images revealed focal areas of increased uptake corresponding to the lesions seen on CT. At surgery, the lesions were confirmed to be synovial cell sarcoma. Imaging with Mabs specific for sarcoma may be particularly useful in sarcoma patients in whom there is clinical uncertainty regarding the nature of pulmonary lesions. In this case, the Mab was useful in distinguishing tumor deposits from postsurgical scarring and helped to guide subsequent surgery and treatment.