Synovial sarcoma of the popliteal fossa

at the time of diagnosis. The patient underwent an extensive surgical resection of tumor with ex-tempore biopsy. Macroscopically, the mass measuring 5×5.5×4 cm was firm, relatively well-circumscribed, and lobulated with a gray-white cut surface. Pathohistological findings showed high-grade primary malignant mesenchymal tumor of the biphasic synovial sarcoma type, cystic subtype that was positive for CK AE1/AE3 focally, CK7 diffuse, CK19 focally, EMA focally-diffuse-1, Vimentin diffuse, Bcl-2 diffuse, CD99 diffuse, Ki-67 positive in > 70% of resection margin and TTF-1, CD34, and CK20 negative. The pathological findings were with viable cells on the margins, so the wide excision was followed by radiotherapy treatment with a total dose of 50 Gray in 25 fractions locally over five weeks. The tumor recurred locally within one year - a follow-up MRI scan after 9 months showed a dominant tumor of 7x7x6.5 cm and one smaller tumor in the distal femoral epiphysis. Tumors had smooth, well defined follow up after one year revealed tumor recurrence. Neurovascular bundle involvement was detected, but without adjacent bone and muscular invasion and above-the-knee partial amputation of the left leg was performed. The intervention resulted in a remission of the neoplastic process and the patient was scheduled for regular check-ups. Broad surgical resection of the tumor with negative margins was the primary treatment in this case. Mutilating operations are necessary when anatomical structures around the tumor do not allow complete reintervention.