A median mandibular cyst is a type of cyst that occurs in the midline of the mandible, thought to be created by proliferation and cystic degeneration of resting epithelial tissue that is left trapped within the substance of the bone during embryologic fusion of the two halves of the mandible, along the plane of fusion later termed the symphysis menti. A true median mandibular cyst would therefore be classified as a non-odontogenic, fissural cyst. The existence of this lesion as a unique clinical entity is controversial, [1] and some reported cases may have represented misdiagnosed odontogenic cysts, [2] which are by far the most common type of intrabony cyst occurring in the jaws. It has also been suggested that the mandible develops as a bilobed proliferation of mesenchyme connected with a central isthmus. Therefore, it is unlikely that epithelial tissue would become trapped as there is no ectoderm separating the lobes in the first instance. [1]
A cyst is a closed sac, having a distinct membrane and division compared with the nearby tissue. Hence, it is a cluster of cells that has 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. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, sometimes 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.
The mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human face. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull.
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin.
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.
The dental follicle, also known as dental sac, is made up of mesenchymal cells and fibres surrounding the enamel organ and dental papilla of a developing teeth. It is a vascular fibrous sac containing the developing tooth and its odontogenic organ. The dental follicle (DF) differentiates into the periodontal ligament. In addition, it may be the precursor of other cells of the periodontium, including osteoblasts, cementoblasts and fibroblasts. They develop into the alveolar bone, the cementum with Sharpey's fibers and the periodontal ligament fibers respectively. Similar to dental papilla, the dental follicle provides nutrition to the enamel organ and dental papilla and also have an extremely rich blood supply.
Oral medicine is a specialty focused on the mouth and nearby structures. It lies at the interface between medicine and dentistry.
Giant-cell fibroma is a type of fibroma not associated with trauma or irritation. It can occur at any age and on a mucous membrane surface. The most common oral locations are on the gingiva of the mandible, tongue, and palate. It is a localized reactive proliferation of fibrous connective tissue.
The Stafne defect is a depression of the mandible on the lingual surface. The Stafne defect is thought to be a normal anatomical variant, as the depression is created by ectopic salivary gland tissue associated with the submandibular gland and does not represent a pathologic lesion as such.
The periapical cyst is the most common odontogenic cyst. Periapical is defined as "the tissues surrounding the apex of the root of a tooth" and a cyst is "a pathological cavity lined by epithelium, having fluid or gaseous content that is not created by the accumulation of pus." Most frequently located in the maxillary anterior region, it is caused by pulpal necrosis secondary to dental caries or trauma. The cyst has lining that is derived from the epithelial cell rests of Malassez which proliferate to form the cyst. Highly common in the oral cavity, the periapical cyst is asymptomatic, but highly significant because a secondary infection can cause pain and damage. In radiographs, it appears a radiolucency around the apex of a tooth's root.
An eruption cyst, or eruption hematoma, is a bluish swelling that occurs on the soft tissue over an erupting tooth. It is usually found in children. The fluid in the cyst is sometimes clear creating a pale-coloured cyst although often they are blue. An eruption cyst is a developmental soft-tissue cyst of odontogenic origin that forms over an erupting tooth.
A primordial cyst is a developmental odontogenic cyst. It is found in an area where a tooth should have formed but is missing. Primordial cysts most commonly arise in the area of mandibular third molars. Under microscopes, the cyst looks like an odontogenic keratocyst whereby the lesions displays a parakeratinized epithelium with palisading basal epithelial cells.
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.
The lateral periodontal cyst is a non-inflammatory developmental cyst that arises from the epithelial post-functional dental lamina, which is a remnant from odontogenesis. It is more common in middle-aged males. Usually asymptomatic, it presents as a regular well-corticated radiolucency on the side of a mandibular canine or premolar root. Histologically, the cyst appears similar to the gingival cyst of the adult, having a non-keratinized squamous epithelial lining. The involved tooth is usually vital and has no indication for root canal treatment unless the signs of non-vital or necrotic pulpal tissue were confirmed. The cysts arise from epithelial rest cells in the periodontal ligament, although it is unknown whether from the cell rests of Malassez, reduced enamel epithelium or dental lamina remnants, and are generally treated by surgical enucleation.
Calcifying odotogenic cyst is a benign odontogenic tumor of cystic type most likely to affect the anterior areas of the jaws. It is most common in people in their second to third decades but can be seen at almost any age. On radiographs, the calcifying odontogenic cyst appears as a unilocular radiolucency. In one-third of cases, an impacted tooth is involved. Microscopically, there are many cells that are described as "ghost cells", enlarged eosinophilic epithelial cells without nuclei.
The glandular odontogenic cyst is a rare odontogenic cyst. In 85% of cases, it is found in the mandible, especially in anterior areas. It is more common in adults in their fifth and sixth decades. On radiographs, it can appear as a unilocular or multilocular radiolucency. Since the glandular odontogenic cyst can range in size, treatment can be as simple as enucleation and curettage to en bloc resection of the affected jaw.
Squamous odontogenic tumors (SOTs) are very rare benign locally infiltrative odontogenic neoplasms of epithelial origin. Only some 50 cases have been documented. They occur mostly from 20-40 and are more common in males. Treatment is by simple enucleation and local curettage, and recurrence is rare.
The odontogenic myxoma is an uncommon benign odontogenic tumor arising from embryonic connective tissue associated with tooth formation. As a myxoma, this tumor consists mainly of spindle shaped cells and scattered collagen fibers distributed through a loose, mucoid material.
The calcifying epithelial odontogenic tumor (CEOT), also known as a Pindborg tumor, is an odontogenic tumor first recognized by the Danish pathologist Jens Jørgen Pindborg in 1955. It was previously described as an adenoid adamantoblastoma, unusual ameloblastoma and a cystic odontoma. Like other odontogenic neoplasms, it is thought to arise from the epithelial element of the enamel origin. It is a typically benign and slow growing, but invasive neoplasm.
The nasopalatine duct cyst (NPDC) occurs in the median of the palate, usually anterior to first molars. It often appears between the roots of the maxillary central incisors. Radiographically, it may often appear as a heart-shaped radiolucency. It is usually asymptomatic, but may sometimes produce an elevation in the anterior portion of the palate. It was first described by Meyer in 1914.
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 together, 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.
Gingival cyst is a type of cysts of the jaws that originates from the dental lamina and is found in the mouth parts. It is a superficial cyst in the alveolar mucosa. It can be seen inside the mouth as small and whitish bulge. Depending on the ages in which they develop, the cysts are classified into gingival cyst of newborn and gingival cyst of adult. Structurally, the cyst is lined by thin epithelium and shows a lumen usually filled with desquamated keratin, occasionally containing inflammatory cells. The nodes are formed as a result of cystic degeneration of epithelial rests of the dental lamina.
This article about a disease of musculoskeletal and connective tissue is a stub. You can help Wikipedia by expanding it. |