A tumor is an abnormal tissue mass that forms when the cells in our body start dividing uncontrollably or do not die when they are supposed to. Musculoskeletal tumors are tumors that develop in muscles, bones and nerves. They can be classified as benign or malignant, and primary or secondary in nature. A benign tumour is a non-cancerous growth that does not intrude nearby tissues or spread to other parts of the body. A malignant tumor is cancerous destroying nearby tissues and can spread to other parts of the body. Primary malignant musculoskeletal tumors originate in muscle or bone whereas secondary tumors have spread from elsewhere in the body to the muscles or bones.
Musculoskeletal tumors can be broadly divided into two major groups namely bone tumors and muscle tumors. Each of these groups is further classified as benign or malignant. The most common benign bone tumors are endochondroma, osteochondroma, nonossifying fibroma, chondroblastoma, osteoid osteoma, osteoblastoma, periosteal chondroma, giant cell tumor, and chondromyxoid fibroma. Malignant bone tumors, although less common, include two subtypes’ namely primary malignant tumors such as osteosarcoma, chondrosarcoma and Ewing’s sarcoma and secondary metastatic tumors that metastasize from the carcinoma of the lung, breast, prostate, kidney or thyroid gland. Benign tumors that arise in the muscles are leiomyomas and rhabdomyomas. Malignant muscle tumors are called leiomyosarcomas and rhabdomyosarcomas.
Benign bone tumors occur most commonly among people below 30 years. They can develop in any bone but most commonly the femur, tibia, humerus and pelvis bone are involved. A lump or swelling that can be felt by touch is usually the first sign of a benign tumor. There will be increasing pain in the region of the tumor which persists over some time. In some cases, the tumor remains undiscovered until there is a fracture in the bone that has become weak from a growing tumor.
Muscles are of 2 types namely smooth muscles and skeletal muscles. Smooth muscles are involuntary muscles that are not under our control and are found in organs such as stomach, intestines, blood vessels or uterus. Skeletal muscles or striated muscles allow movements of our arms and legs and other parts of the body. Benign muscle tumors are of two types called leiomyomas and rhabdomyomas.
Leiomyomas arise in the smooth muscles and develop in the walls of blood vessels. Most commonly, they are found in the uterine wall and are called fibroids. Rhabdomyomas are benign tumors of the skeletal muscles and are rare.
Malignant muscle tumors include leiomyosarcomas and rhabdomyosarcomas. Leiomyosarcomas are malignancies arising in the smooth muscles and often occur in internal organs, blood vessels and at the back of the abdominal cavity. They occur in adults especially at an elderly age.
Rhabdomyosarcomas are cancers that consist of cells that would normally develop into skeletal muscles. This tumor commonly affects children rather than adults. The arms, legs, head and neck region, urinary and reproductive organs such as vagina, bladder and prostate gland are the common sites where this tumor may occur. The two main subtypes of rhabdomyosarcomas include embryonal rhabdomyosarcomas and alveolar rhabdomyosarcomas. Embryonal rhabdomyosarcoma affects infants and young children. It occurs in the head and neck region, bladder, vagina or prostate. Alveolar rhabdomyosarcoma affects teenagers and older children. Often, large muscles of the arms, legs and abdomen are affected.
Treatment involves surgery to remove the tumor prior to which chemotherapy or radiation therapy may be used to shrink the growth.
In recent years, there have been noticeable improvements in the treatment and prognosis of patients with musculoskeletal tumors. This is because of advances in imaging and surgical techniques and the advent of newer chemotherapeutic drugs.