A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, thyroid, kidney and prostate. There may be a lump, pain, or neurological signs from pressure. A bone tumor might present with a pathologic fracture. Other symptoms may include fatigue, fever, weight loss, anemia and nausea. Sometimes there are no symptoms and the tumour is found when investigating another problem.
An osteosarcoma (OS) or osteogenic sarcoma (OGS) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin and that exhibits osteoblastic differentiation and produces malignant osteoid.
Sex cord–gonadal stromal tumour is a group of tumours derived from the stromal component of the ovary and testis, which comprises the granulosa, thecal cells and fibrocytes. In contrast, the epithelial cells originate from the outer epithelial lining surrounding the gonad while the germ cell tumors arise from the precursor cells of the gametes, hence the name germ cell. In humans, this group accounts for 8% of ovarian cancers and under 5% of testicular cancers. Their diagnosis is histological: only a biopsy of the tumour can make an exact diagnosis. They are often suspected of being malignant prior to operation, being solid ovarian tumours that tend to occur most commonly in post menopausal women.
The metaphysis is the neck portion of a long bone between the epiphysis and the diaphysis. It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses. The metaphysis contains a diverse population of cells including mesenchymal stem cells, which give rise to bone and fat cells, as well as hematopoietic stem cells which give rise to a variety of blood cells as well as bone-destroying cells called osteoclasts. Thus the metaphysis contains a highly metabolic set of tissues including trabecular (spongy) bone, blood vessels, as well as marrow adipose tissue (MAT).
A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize. Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have relatively well differentiated cells. They are often surrounded by an outer surface or stay contained within the epithelium. Common examples of benign tumors include moles and uterine fibroids.
Ameloblastoma is a rare, benign or cancerous tumor of odontogenic epithelium much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack. This type of odontogenic neoplasm was designated as an adamantinoma in 1885 by the French physician Louis-Charles Malassez. It was finally renamed to the modern name ameloblastoma in 1930 by Ivey and Churchill.
Enchondroma is a type of benign bone tumor belonging to the group of cartilage tumors. There may be no symptoms, or it may present typically in the short tubular bones of the hands with a swelling, pain or pathological fracture.
Giant-cell tumor of the bone (GCTOB), is a relatively uncommon bone tumor. It is characterized by the presence of multinucleated giant cells. Malignancy in giant-cell tumor is uncommon and occurs in about 2% of all cases. However, if malignant degeneration does occur, it is likely to metastasize to the lungs. Giant-cell tumors are normally benign, with unpredictable behavior.
Warthin's tumor, also known as papillary cystadenoma lymphomatosum, is a benign cystic tumor of the salivary glands containing abundant lymphocytes and germinal centers. It is named for pathologist Aldred Scott Warthin, who described two cases in 1929.
Nodular fasciitis (NF) is a benign, soft tissue tumor composed of myofibroblasts that typically occurs in subcutaneous tissue, fascia, and/or muscles. The literature sometimes titles rare NF variants according to their tissue locations. The most frequently used and important of these are cranial fasciitis and intravascular fasciitis. In 2020, the World Health Organization classified nodular fasciitis as in the category of benign fibroblastic/myofibroblastic tumors. NF is the most common of the benign fibroblastic proliferative tumors of soft tissue.
Central giant-cell granuloma (CGCG) is a localised benign condition of the jaws. It is twice as common in females and is more likely to occur before age 30. Central giant-cell granulomas are more common in the anterior mandible, often crossing the midline and causing painless swellings.
An odontogenic keratocyst is a rare and benign but locally aggressive developmental cyst. It most often affects the posterior mandible and most commonly presents in the third decade of life. Odontogenic keratocysts make up around 19% of jaw cysts. Despite its more common appearance in the bone region, it can affect soft tissue.
Chondroblastoma is a rare, benign, locally aggressive bone tumor that typically affects the epiphyses or apophyses of long bones. It is thought to arise from an outgrowth of immature cartilage cells (chondroblasts) from secondary ossification centers, originating from the epiphyseal plate or some remnant of it.
Osteoblastoma is an uncommon osteoid tissue-forming primary neoplasm of the bone.
An osteoid osteoma is a benign (non-cancerous) bone tumor that arises from osteoblasts and some components of osteoclasts. It was originally thought to be a smaller version of an osteoblastoma. Osteoid osteomas tend to be less than 1.5 cm in size. The tumor can be in any bone in the body but are most common in long bones, such as the femur and tibia. They account for 10 to 12 percent of all benign bone tumors and 2 to 3 percent of all abnormal bone growths. Osteoid osteomas may occur at any age, and are most common in patients between the ages of 4 and 25 years old. Males are affected approximately three times more commonly than females.
Ubiquitin carboxyl-terminal hydrolase 6 (USB6), also termed TRE17 and Tre-2, is a deubiquitinating enzyme that in humans is encoded by the hominid USP6 gene located at band 13.2 on the short arm of chromosome 17. Deubiquitinating enzymes (DUBs) are enzymes that act within cells to remove ubiquitins from various functionally important proteins. Ubiquitin enzymes add ubiquitin to these proteins and thereby regulate their cellular location, alter their activity, and/or promote their degradation. By deubiquitinating these proteins, DUBs counter the effects of the ubiquinating enzymes and contribute to regulating the actions of the targeted proteins. In normal adult tissues, USP6 is highly expressed in testicle tissue, modestly expressed in ovarian tissue, and absent or minimally expressed in other tissues. It is also highly expressed in fetal brain tissue. The specific functions of USP6 are poorly defined primarily because its presence is restricted to primates: there are no available animal models to determine the effects of its deletion, although some studies suggest that UPSP6 contributes to normal brain development. In all events, USP6 has gained wide interest because of its abnormally increased expression by the neoplastic cells in various tumors derived from mesenchymal tissue.
A bone cyst or geode is a cyst that forms in bone.
Cysts of the jaws are cysts—pathological epithelial-lined cavities filled with fluid or soft material—occurring on the bones of the jaws, the mandible and maxilla. Those are the bones with the highest prevalence of cysts in the human body, due to the abundant amount of epithelial remnants that can be left in the bones of the jaws. The enamel of teeth is formed from ectoderm, and so remnants of epithelium can be left in the bone during odontogenesis. The bones of the jaws develop from embryologic processes which fuse, and ectodermal tissue may be trapped along the lines of this fusion. This "resting" epithelium is usually dormant or undergoes atrophy, but, when stimulated, may form a cyst. The reasons why resting epithelium may proliferate and undergo cystic transformation are generally unknown, but inflammation is thought to be a major factor. The high prevalence of tooth impactions and dental infections that occur in the bones of the jaws is also significant to explain why cysts are more common at these sites.
A unicameral bone cyst, also known as a simple bone cyst, is a cavity filled with a yellow-colored fluid. It is considered to be benign since it does not spread beyond the bone. Unicameral bone cysts can be classified into two categories: active and latent. An active cyst is adjacent to the epiphyseal plate and tends to grow until it fills the entire diaphysis, the shaft, of the bone; depending on the invasiveness of the cyst, it can cause a pathological fracture or even destroy the epiphyseal plate leading to the permanent shortening of the bone.
Proliferative fasciitis and proliferative myositis (PF/PM) are rare benign soft tissue lesions that increase in size over several weeks and often regress over the ensuing 1–3 months. The lesions in PF/PM are typically obvious tumors or swellings. Historically, many studies had grouped the two descriptive forms of PF/PM as similar disorders with the exception that proliferative fasciitis occurs in subcutaneous tissues while proliferative myositis occurs in muscle tissues. In 2020, the World Health Organization agreed with this view and defined these lesions as virtually identical disorders termed proliferative fasciitis/proliferative myositis or proliferative fasciitis and proliferative myositis. The Organization also classified them as one of the various forms of the fibroblastic and myofibroblastic tumors.
