A unicameral bone cyst is a fluid-filled cavity that forms inside a bone, usually in children and teenagers. It typically appears in long bones, like those in the arms or legs. These cysts are usually not cancerous and can sometimes be found during X-rays taken for other reasons. They may not cause any symptoms, but if they grow large, they can weaken the bone, leading to pain or fractures. Treatment can include monitoring the cyst or, in some cases, surgery to fill it in with bone grafting material to strengthen the bone.

An aneurysmal bone cyst is a benign (non-cancerous) bone growth that looks like a fluid-filled bubble inside the bone. It often occurs in children and teenagers and can happen in various bones, like the spine, arms, or legs. These cysts can cause pain or even fractures because they can weaken the bone. They might be found incidentally during X-rays or other imaging tests. Treatment may involve curettage (scraping of the lesion) and filling the cavity with bone graft.

A liposclerosing myxofibrous tumor is a rare type of tumor that usually occurs in the bones, particularly the top part of the femur bone. This tumor is a mix of different types of tissues, including fat (lipo), fibrous tissue, and a jelly-like (myxoid) substance. These tumors are typically non-cancerous (benign) but can cause pain or swelling in the affected area. They may be discovered incidentally during X-rays or other imaging tests. Treatment usually involves monitoring the tumor. A recommendation for surgery may be made if there is a fracture through the lesion (pathologic fracture) or if there is a high risk of a fracture occurring (impending fracture).