Chondrosarcoma: A slowly growing malignant neoplasm derived from cartilage cells, occurring most frequently in pelvic bones or near the ends of long bones, in middle-aged and old people. Most chondrosarcomas arise de novo, but some may develop in a preexisting benign cartilaginous lesion or in patients with ENCHONDROMATOSIS. (Stedman, 25th ed)Chondrosarcoma, Mesenchymal: A rare aggressive variant of chondrosarcoma, characterized by a biphasic histologic pattern of small compact cells intermixed with islands of cartilaginous matrix. Mesenchymal chondrosarcomas have a predilection for flat bones; long tubular bones are rarely affected. They tend to occur in the younger age group and are highly metastatic. (DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1456)Chondroma: A benign neoplasm derived from mesodermal cells that form cartilage. It may remain within the substance of a cartilage or bone (true chondroma or enchondroma) or may develop on the surface of a cartilage (ecchondroma or ecchondrosis). (Dorland, 27th ed; Stedman, 25th ed)Bone Neoplasms: Tumors or cancer located in bone tissue or specific BONES.Enchondromatosis: Benign growths of cartilage in the metaphyses of several bones.Chordoma: A malignant tumor arising from the embryonic remains of the notochord. It is also called chordocarcinoma, chordoepithelioma, and notochordoma. (Dorland, 27th ed)Myxosarcoma: A sarcoma, usually a liposarcoma or malignant fibrous histiocytoma, with an abundant component of myxoid tissue resembling primitive mesenchyme containing connective tissue mucin. (Stedman, 25th ed)Cartilage: A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE.Femoral NeoplasmsSkull Base Neoplasms: Neoplasms of the base of the skull specifically, differentiated from neoplasms of unspecified sites or bones of the skull (SKULL NEOPLASMS).Exostoses, Multiple Hereditary: Hereditary disorder transmitted by an autosomal dominant gene and characterized by multiple exostoses (multiple osteochondromas) near the ends of long bones. The genetic abnormality results in a defect in the osteoclastic activity at the metaphyseal ends of the bone during the remodeling process in childhood or early adolescence. The metaphyses develop benign, bony outgrowths often capped by cartilage. A small number undergo neoplastic transformation.Neoplasms, Connective and Soft Tissue: Neoplasms developing from some structure of the connective and subcutaneous tissue. The concept does not refer to neoplasms located in connective or soft tissue.Osteosarcoma: A sarcoma originating in bone-forming cells, affecting the ends of long bones. It is the most common and most malignant of sarcomas of the bones, and occurs chiefly among 10- to 25-year-old youths. (From Stedman, 25th ed)Ribs: A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs.Pelvic Bones: Bones that constitute each half of the pelvic girdle in VERTEBRATES, formed by fusion of the ILIUM; ISCHIUM; and PUBIC BONE.Chondroitinases and Chondroitin Lyases: Enzymes which catalyze the elimination of glucuronate residues from chondroitin A,B, and C or which catalyze the hydrolysis of sulfate groups of the 2-acetamido-2-deoxy-D-galactose 6-sulfate units of chondroitin sulfate. EC 4.2.2.-.Chondromatosis, Synovial: Rare, benign, chronic, progressive metaplasia in which cartilage is formed in the synovial membranes of joints, tendon sheaths, or bursae. Some of the metaplastic foci can become detached producing loose bodies. When the loose bodies undergo secondary calcification, the condition is called synovial osteochondromatosis.Proteoglycans: Glycoproteins which have a very high polysaccharide content.Osteochondroma: A cartilage-capped benign tumor that often appears as a stalk on the surface of bone. It is probably a developmental malformation rather than a true neoplasm and is usually found in the metaphysis of the distal femur, proximal tibia, or proximal humerus. Osteochondroma is the most common of benign bone tumors.Maxillary Neoplasms: Cancer or tumors of the MAXILLA or upper jaw.