| Bone cyst | |
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| A bone cyst in the vertebra of the neck as seen on CT | |
| Specialty | Rheumatology  |
A bone cyst or geode is a cyst that forms in bone.
Types include:
On CT scans, bone cysts that have a radiodensity of 20 Hounsfield units (HU) or less, and are osteolytic, tend to be aneurysmal bone cysts. [1]
In contrast, intraosseous lipomas have a lower radiodensity of -40 to -60 HU. [2]
Some unicameral bone cysts may spontaneously resolve without medical intervention. Specific treatments are determined based on the size of the cyst, the strength of the bone, medical history, extent of the disease, activity level, symptoms an individual is experiencing, and tolerance for specific medications, procedures, or therapies. [3] The types of methods used to treat this type of cyst are curettage and bone grafting, aspiration, steroid injections, and bone marrow injections. Watchful waiting and activity modifications are the most common nonsurgical treatments that will help resolve and help prevent unicameral bone cysts from occurring and reoccurring. [4]
Aneurysmal bone cysts can be treated with a variety of different methods. These methods include open curettage and bone grafting with or without adjuvant therapy, cryotherapy, sclerotherapy, ethibloc injections, radionuclide ablation, and selective arterial embolization. [5] En bloc resection and reconstruction with strut grafting are the most common treatments and procedures that prevent recurrences of this type of cyst. [6]
The traumatic bone cyst treatment consists of surgical exploration, curettage of the osseous socket and bony walls, subsequent filling with blood, and intralesional steroid injections. [7] Young athletes can reduce their risk of traumatic bone cyst by wearing protective mouth wear or protective headgear. [8]
Aneurysmal bone cysts are benign neoformations which can affect any bone. More than half occur in the metaphysis of long bones (especially femur and tibia) and between 12 and 30% in the spine. They were described in 1893 by Van Arsdale, [9] who called these lesions "homerus ossifying haematoma". In 1940 Ewing used the term "aneurismal" to describe these lesions. [10] Jaffé and Lichtenstein first coined the term "aneurismal cyst" in 1942 [11] In 1950 they modified this term to "aneurismal bone cyst". They may be associated with bone tumors.
The simple bone cyst is a common, benign, fluid-containing lesion, most commonly found in the metaphysis of long bones, typically the proximal humerus or femur. Pathologic fractures are common, often with minor trauma. These cysts typically resolve after skeletal maturity and are not typically associated with bone tumors. The cause is unknown. These were first recognised as a distinct entity in 1910. [12] Jaffe and Lichtenstein provided a detailed discussion of simple bone cysts in 1942. [11]
The traumatic bone cyst, also referred to as a simple bone cyst or hemorrhagic cyst, is a pseudocyst that most commonly affects the mandible of young individuals. It is a benign empty or fluid-containing cavity within the mandible body that does not have evidence of a true epithelial lining. This type of bone cyst is a condition found in the long bones and jaws. [13] There is no definitive cause, though it relates to trauma in the oral region. The likelihood of males being affected by this condition is frequently greater than in females. It appears on radiographs as a unilocular radiolucent area with an irregular but well-defined outline. This term was first described by Lucas in 1929. [8]
A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac ; however, the distinguishing aspect of a cyst is that the cells forming the "shell" of such a sac are distinctly abnormal when compared with all surrounding cells for that given location. A cyst may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst may resolve on its own. When a cyst fails to resolve, it may need to be removed surgically, but that would depend upon its type and location.
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.
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.
Giant-cell tumor of the bone (GCTOB), is a relatively uncommon tumor of the bone. 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. It is a heterogeneous tumor composed of three different cell populations. The giant-cell tumour stromal cells (GCTSC) constitute the neoplastic cells, which are from an osteoblastic origin and are classified based on expression of osteoblast cell markers such as alkaline phosphatase and osteocalcin. In contrast, the mononuclear histiocytic cells (MNHC) and multinucleated giant cell (MNGC) fractions are secondarily recruited and comprise the non-neoplastic cell population. They are derived from an osteoclast-monocyte lineage determined primarily by expression of CD68, a marker for monocytic precursor cells. In most patients, the tumors are slow to develop, but may recur locally in as many as 50% of cases.
Aneurysmal bone cyst (ABC) is a non-cancerous bone tumor composed of multiple varying sizes of spaces in a bone which are filled with blood. The term is a misnomer, as the lesion is neither an aneurysm nor a cyst. It generally presents with pain and swelling in the affected bone. Pressure on neighbouring tissues may cause compression effects such as neurological symptoms.
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.
Calcifying odotogenic cyst (COC) is a rare developmental lesion that comes from odontogenic epithelium. It is also known as a calcifying cystic odontogenic tumor, which is a proliferation of odontogenic epithelium and scattered nest of ghost cells and calcifications that may form the lining of a cyst, or present as a solid mass.
A glandular odontogenic cyst (GOC) is a rare and usually benign odontogenic cyst developed at the odontogenic epithelium of the mandible or maxilla. Originally, the cyst was labeled as "sialo-odontogenic cyst" in 1987. However, the World Health Organization (WHO) decided to adopt the medical expression "glandular odontogenic cyst". Following the initial classification, only 60 medically documented cases were present in the population by 2003. GOC was established as its own biological growth after differentiation from other jaw cysts such as the "central mucoepidermoid carcinoma (MEC)", a popular type of neoplasm at the salivary glands. GOC is usually misdiagnosed with other lesions developed at the glandular and salivary gland due to the shared clinical signs. The presence of osteodentin supports the concept of an odontogenic pathway. This odontogenic cyst is commonly described to be a slow and aggressive development. The inclination of GOC to be large and multilocular is associated with a greater chance of remission. GOC is an infrequent manifestation with a 0.2% diagnosis in jaw lesion cases. Reported cases show that GOC mainly impacts the mandible and male individuals. The presentation of GOC at the maxilla has a very low rate of incidence. The GOC development is more common in adults in their fifth and sixth decades.
An ameloblastic fibroma is a fibroma of the ameloblastic tissue, that is, an odontogenic tumor arising from the enamel organ or dental lamina. It may be either truly neoplastic or merely hamartomatous. In neoplastic cases, it may be labeled an ameloblastic fibrosarcoma in accord with the terminological distinction that reserves the word fibroma for benign tumors and assigns the word fibrosarcoma to malignant ones. It is more common in the first and second decades of life, when odontogenesis is ongoing, than in later decades. In 50% of cases an unerupted tooth is involved.
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.
A non-ossifying fibroma (NOF) is a benign bone tumor of the osteoclastic giant cell-rich tumor type. It generally occurs in the metaphysis of long bones in children and adolescents. Typically, there are no symptoms unless there is a fracture. It can occur as part of a syndrome such as when multiple non-ossifying fibromas occur in neurofibromatosis, or Jaffe-Campanacci syndrome in combination with cafe-au-lait spots, mental retardation, hypogonadism, eye and cardiovascular abnormalities.
A vascular anomaly is any of a range of lesions from a simple birthmark to a large tumor that may be disfiguring. They are caused by a disorder of the vascular system. A vascular anomaly is a localized defect in blood or lymph vessels. These defects are characterized by an increased number of vessels, and vessels that are both enlarged and sinuous. Some vascular anomalies are congenital, others appear within weeks to years after birth, and others are acquired by trauma or during pregnancy. Inherited vascular anomalies are also described and often present with a number of lesions that increase with age. Vascular anomalies can also be a part of a syndrome.
Odontogenic cyst are a group of jaw cysts that are formed from tissues involved in odontogenesis. Odontogenic cysts are closed sacs, and have a distinct membrane derived from rests of odontogenic epithelium. It may contain air, fluids, or semi-solid material. Intra-bony cysts are most common in the jaws, because the mandible and maxilla are the only bones with epithelial components. That odontogenic epithelium is critical in normal tooth development. However, epithelial rests may be the origin for the cyst lining later. Not all oral cysts are odontogenic cyst. For example, mucous cyst of the oral mucosa and nasolabial duct cyst are not of odontogenic origin.
In addition, there are several conditions with so-called (radiographic) 'pseudocystic appearance' in jaws; ranging from anatomic variants such as Stafne static bone cyst, to the aggressive aneurysmal bone cyst.
A cyst is a pathological epithelial lined cavity that fills with fluid or soft material and usually grows from internal pressure generated by fluid being drawn into the cavity from osmosis. The bones of the jaws, the mandible and maxilla, are the bones with the highest prevalence of cysts in the human body. This is 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.
Pancreatic mucinous cystic neoplasm (MCN) is a type of cystic lesion that occurs in the pancreas. Amongst individuals undergoing surgical resection of a pancreatic cyst, about 23 percent were mucinous cystic neoplasms. These lesions are benign, though there is a high rate of progression to cancer. As such, surgery should be pursued when feasible. The rate of malignancy present in MCN is about 10 percent. If resection is performed before invasive malignancy develops, prognosis is excellent. The extent of invasion is the single most important prognostic factor in predicting survival.
| Authority control: National |
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