Extraskeletal myxoid chondrosarcoma: An analysis of 34 cases

Abstract Myxoid chondrosarcoma arising from extraskeletal soft tissues is a comparatively rare neoplasm characterized by ill defined nodular masses composed of cords and strands of small acidophilic cells separated by abundant mucoid stroma. Cartilaginous origin of the cells is suggested by their close resemblance to developing chondroblasts, the staining reactions of the mucoid ground substance indicating the presence of large amounts of sulfated mucopolysaccharides, and the electron microscopic findings. All 34 tumors of this series occurred in the extremities; 24 involved muscle tissue or were intimately attached to tendons or ligaments. Their size ranged from 1.5 to 23 cm. The ages of the patients ranged from 13 to 89 years, with a mean of 49 years. Recognition of this tumor and clear distinction from chondrosarcoma of bone are of particular importance because of the difference in behavior. Of the 31 patients with follow-up information, 11 had died—four of metastatic neoplasms and seven of unrelated intercurrent disease. Twenty were alive, but during the follow-up period four of the living patients developed recurrences; one, metastasis; and two, recurrence and metastasis. It is remarkable that all three living patients with metastasis were still alive 10, 12, and 20 years after the initial surgery.