Pulmonary Embolism in a Patient with Primary Renal Synovial Sarcoma: The Important Differential Diagnosis of Tumor Embolism and Its Therapeutic Implications
We report the case of a 52-year-old man with synovial sarcoma of the right kidney. Laparoscopic nephroureterectomy was performed in January 2012, under the suspicion of renal cell carcinoma (fig. ). The postoperative course was complicated by pulmonary embolism. The patient was put on anticoagulant therapy with low-molecular-weight heparin.\nSurprisingly, the histologic findings were compatible with synovial sarcoma, verified by the detection of the typical t(X, 18) translocation and the SYT/SSX fusion gene. The initial assessment confirmed stage III disease: pT2b (maximum tumor size 8.2 cm), Nx M0 V1 (formation of a tumor thrombus in the right renal vein) G3.\nAccording to a meta-analysis published in 1997, adjuvant chemotherapy can prolong progression-free survival, and there is a trend towards prolonged overall survival []. Further prospective studies have evaluated this question, and in high-grade soft tissue sarcomas adjuvant chemotherapy can be considered []. Adjuvant chemotherapy was discussed with our patient and, bearing in mind the high risk of recurrence in this case (tumor size, histologic grading and angioinvasion), 4 cycles of adjuvant chemotherapy with doxorubicin and ifosfamide were applied []. At the end of the treatment visit, a CT scan was performed and no tumor could be detected, but there was still evidence of a pulmonary embolus in the left inferior lobe. Subsequently, the patient was kept on anticoagulant therapy with low-molecular-weight heparin.\nAt the first follow-up visit 4 months after the completion of adjuvant chemotherapy, there was still no evidence of local tumor recurrence or metastases; however, in the area of the left inferior lobe pulmonary artery, a persisting soft tissue formation of unknown etiology could be documented. This entity was deemed most likely to be scar tissue after thromboembolism with pulmonary infarction or residual thrombus.\nIn the further follow-up period 3 months later, a CT scan showed progression of this soft tissue formation with partial occlusion of the left inferior lobe pulmonary artery (fig. ); no uptake could be shown on PET/CT (fig. ). Subsequently, a bronchoscopy with endobronchial ultrasound-guided transbronchial needle aspiration was performed for tissue sampling of the endoluminal thrombus. Histology revealed a spindle cell proliferation, which was compatible with metastasis of the known synovial sarcoma. At this time, no other sites of active disease could be detected on CT. Following data favoring metastasectomy in isolated pulmonary metastasis in selected patients [], a lobectomy of the left lower lobe with subsequent resection of the lingula and bronchoplasty were performed (fig. ). Histology confirmed a synovial sarcoma metastasis (fig. ).\nWritten informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent form is available for review from the editor of this journal.