Overview of bone and joint tumors

[Greta]

Bone tumors may be benign or malignant. Malignant tumors may be primary or metastatic.
In children, most bone tumors are primary and benign; some are malignant primary tumors (eg, osteosarcoma, Ewing sarcoma). Very few are metastatic tumors (eg, neuroblastoma, Wilms tumor). Bone marrow also can be affected by childhood leukemia and lymphomas.
In adults, especially those over age 40, metastatic tumors are about 100 times more common than primary malignant tumors. Excluding marrow cell tumors (eg, multiple myeloma), there are only about 2500 cases of primary malignant bone tumors in the US each year among children and adults.
Synovial tumors are extremely rare in both children and adults. Pigmented villonodular synovitis (PVNS and also known as tenosynovial giant cell tumor) is a benign but at times destructive tumor of synovial cells. Synovial sarcoma (often with both spindle cell and glandular–like components) is a malignant soft-tissue tumor not of synovial origin, which seldom occurs inside of a joint.