Bone tumors often cause bumps on the femur bone, according to Healthline. Tumors are either benign, which means noncancerous, or malignant, meaning cancerous. Benign bone tumors grow but do not spread to other areas of the body. Malignant tumors can spread and cause cancer.
Types of benign bone tumors include osteochondromas, nonossifying fibroma unicameral and giant cell tumors, details Healthline. Osteochondromas tumors usually impact the femur, tibia and humerus and account for as much as 40 percent of all benign bone tumors. Nonossifying fibroma unicameral typically affects children and adolescents and is a single bone cyst. Giant cell tumors are rare, affect adults and grow aggressively.
Osteosarcoma, Ewing sarcoma family of tumors and chondrosarcoma are examples of malignant bone tumors, advises Healthline. Osteosarcoma is the second-most-common type of bone cancer and is most common in children and adolescents. Ewing sarcoma family of tumors impact young adults, adolescents and children as young as 5 years old. Chondrosarcoma most often affects people middle-aged and older.
The cause of bone tumors is unknown, but rapid growth, radiation, bone injuries and genetics are possible causes, explains Healthline. Osteosarcoma in children is linked to high doses of radiation, and osteosarcoma is more likely if a bone fracture is repaired with metal implants.