Abstract
A case of extraskeletal myxoid chondrosarcoma arising around the ankle joint is reported. A 68-year-old woman noticed a mass lesion on the lateral aspect of her left ankle joint about one year ago. Because she had no pain, she neglected this mass. At her first visit, the elastic hard mass of 6 × 5 cm in size was palpable on the lateral aspect of her left ankle joint. No symptoms, tenderness, knock pain, and Tinel's sign were observed of the lesion. X-ray showed no calcification on the extra-articular region. MR imaging showed this tumor multinodular pattern, and low signal intensity in T1 weighed image and high signal intensity in the T2 weighed image. Open biopsy was performed, a tan-gray colored gelatinous specimen were obtained. Histopathologically, round cells, which had eosinophylic cytoplasm, grew in a cord-like and/or nest. The tumor stained positively in S100 protein and chromogranin-A, immunohistochemically. From these findings, this tumor was diagnosed as extraskeletal myxoid chondrosarcoma easily. It was difficult to resect this tumor with curative margin, so amputation below knee was performed. After three months of operation, she has no recurrences and metastases, and she can walk with below knee prosthesis.
