Cysts Of the Oral & Paraoral Regions PDF

1 CYSTS OF THE ORAL AND PARAORAL REGIONS Definition: A cyst is a pathological cavity lined by epithelium contain …..fluid or a semi-fluid material. pseudocysts : cysts …..not lined by epithelium Classification: 1-Odontogenic cysts arise from od...

1 CYSTS OF THE ORAL AND PARAORAL REGIONS Definition: A cyst is a pathological cavity lined by epithelium contain …..fluid or a semi-fluid material. pseudocysts : cysts …..not lined by epithelium Classification: 1-Odontogenic cysts arise from odontogenic epithelial cells. a. periodontal cysts inflammatory: 1- apical 2- lateral 3- residual developmental : 1. lateral developmental cysts. 2- gingival cyst of adults. 3-. gingival cyst of newborn (Bohn's nodules). b. Dentigerous cyst: (Central, lateral, circumferential). c. Primordial cyst, odontogenic keratocyst. 2- Non-Odontogenic cysts  2 a. Nasopalatine Cysts: 1- Incisive Canal Cyst. 2- Cyst of palatine papilla. b. Fissural Cysts: 1- Globulomaxillary cyst. 2- Nasolabial cyst. 3- Median Cysts: In the maxilla: median palatal cyst In the mandible: median mandibular cyst. 3- Pseudocysts a - Traumatic bone cyst. b- Aneurismal bone cyst c- Static bone cyst. 4- Soft tissue cysts of the jaw and neck a- Dermoid and epidermoid cysts. b- Thyroglossal tract cyst. c- Benign lymphoepithelial cyst (branchial-cleft cyst). d- Mucous retention and mucous extravasation cysts. 1- ODONTOGENIC CYSTS  3 The epithelium associated with odontogenic cysts is derived from: 1. Enamel organ. 2. Reduced enamel epithelium. 3. Epithelial rests of Malassez. 4., epithelial rests of serres. a - Periodontal cysts Inflammatory periodontal cysts: 1-Apical (periapical, radicular) cyst etiology and Pathogenesis: This cyst represents 65% of all cysts. It results from inflammatory hyperplasia of the epithelial rests of Malassez in the periodontal ligament following death of the pulp. It is either apical or periapical (related to root apex) or lateral (related to lateral root surface and accessory root canal) or residual left after extraction in edentulous area of jaw. Periapical cysts develop form periapical granuloma. (caused by the inflammatory hyperplasia within the granuloma). As this proliferation continues, the epithelial mass increases in size , the cells in the central portion of the mass become separated from their source of nutrition the capillaries of the connective tissue. As these central cells fail to obtain sufficient nutrients, they eventually degenerate, become necrotic and liquefy.  4 This creates an epithelial lined cavity filled with fluid, forming the apical periodontal cyst. Uncommonly …cyst may form through proliferation of epithelium to line a pre-existing cavity formed through focal necrosis of connective tissue in a periapical granuloma; Mechanism of Enlargement: Remnants of cellular debris within the cyst lumen producing an increase in osmotic pressure of the cystic fluid as a result of the breakdown of complex tissue proteins into a larger number of molecules of more simple proteins. The result is fluid transport across the epithelial linning that act as a semipermeable membrane. Fluid ingress into the lumen results in cyst enlargement Clinical Features: Age: Adult (third to the sixth decades) Sex: More in men. Site: Maxilla especially the anterior region. Most radicular cysts are asymptomatic and are discovered during routine x-ray examination. slowly progressive painless swellings If infection occurs, the swelling becomes painful and may rapidly increase in size 1- At first The swelling is rounded and hard. − Later, bone has been reduced to eggshell crackling,  5 ( felt on pressure ). − Finally the overlying bone is resorbed leaving a soft fluctuant swelling, bluish in colour,. − There is usually a non-vital tooth from which the cyst has developed. Radiographically: −Round or ovoid well-defined radiolucency ,thin opaque margin. 2- cyst ranges from 5mm to several centimeters in diameter −Root resorption of the offending tooth −Infection of a cyst causes the outline to become hazy. − small radicular cyst and a periapical granuloma radio-graphically is nearly the same Microscopic Variations in Cyst Walls: − The epithelial linning of apical periodontal cysts is: a-stratified squamous epithelium, b-respiratory or Pseudo-stratified ciliated columnar epithelium. This may be seen in cysts of maxillary teeth, which involve maxillary sinus. c-embryonic epithelium - In a newly formed cyst, the epithelium is hyper-plastic -In fully formed cysts, the epithelial linning becomes regular and  6 flattened , connective tissue contains few inflammatory cells. 2− The connective tissue linning of apical periodontal cysts is : 1- collagen fibers ,fibroblasts and capillaries. − acute and chronic inflammatory cells − foci of Dystrophic calcification as haematoxyphilic masses in the epithelium and. connective tissue. 4- cholesterol clefts 5- Degenerated plasma cells ( Russel bodies) 6- eosinophilic Hyaline bodies or Rushton bodies (Thin , curved bodies, such bodies is arising from red blood cells in small capillaries, found within the epithelial lining. 7- Multinucleated giant cells 8- lipid-filled macrophages (foam cells) cystic fluid : contains serum albumin, globulin, cholesterol and nucleoproteins. Differential Diagnosis: 1- Periapical granuloma if the radiolucency is small, − Periapical scar in areas of previously treated periapical pathology. −Early phase of periapical cemental dysplasia in anterior mandibular, area, but related teeth are usually vital. Treatment 1- -the cyst is small, enucleation of the cyst and apicectomy of the involved tooth.  7 2- The medium size, remove the tooth and enucleate the cyst. 3- Large cysts need marsupialization to avoid the antrum or important structures as the inferior dental nerve. − Larger cysts need enucleation and bone chips to fill the cavity. 2- inflammatory Lateral Periodontal Cysts: Inflammatory lateral periodontal cysts are less common than periapical ones. They form at the side of the root of a pulpless tooth as a result of opening of a lateral root canal and irritation of periodontal tissue. 3- Residual Cyst: The pulpless tooth (with a periapical cyst) The tooth was extracted and the cyst may persist in the jaw bone.. Residual cysts may cause trouble with dentures, and sometimes enlarge to the extent of weakening the jaw with possible risk of jaw fracture. Developmental Periodontal Cysts: 1- developmental Lateral Periodontal Cyst: Definition: Non-inflammatory developmental cyst occurring adjacent or lateral to the root of a vital tooth.  8 Aetiology and Pathogenesis: The origin is related to proliferation of rests of the dental lamina. ( no inflammation or irritations ) Clinical features: Age: any age, commonest age from 40 to 60 years, Sex: Male to female ratio 2:1. Site: common sites are the mandibular premolar and canine region. the maxilla the lateral incisor region. Appearance: no signs or symptoms and may be discovered during routine radiographic examination the overlying mucosa is normal. The related tooth is vital. If the cyst becomes infected, it may resemble a lateral periodontal abscess. Radiographic features: Small radiolucent area. seldom over 1cm in diameter. May be with an opaque margin. Histopathologic Features: thin stratified squamous epithelium Parakeratin or orthokeratin formation. Inflammatory cells may be present in the connective tissue  9 wall but this is a secondary inflammatory reaction. 2- Developmental Gingival Cyst of Adulthood: as non-inflammatory developmental cyst occurring adjacent a vital tooth at gingiva. Aetiology and Pathogenesis: Gingival cyst arises from dental lamina remnants in the soft the tissue between the oral epithelium and the periosteum. Clinical Features: Age: any age commonest 40-60 years. Sex: males and females are almost equally affected Appearance: gingival cysts appear as a small, well-circumscribed painless swelling of the gingiva of less than 1cm in diameter. The lesion has-the same colour as the adjacent normal mucosa Radiographic Features: dental x-ray film (-ve). Histopathologic Features: The epithelium is very thin, flattened squamous epithelium.  10 3 -Gingival Cyst of the New Born (Bohn 's Nodules): These are multiple white nodules of not more than a few millimeters in diameter on the alveolar ridge of a new from infant originating from remnants of the dental lamina which proliferate to form small keratinized cysts. These lesions appear to be asymptomatic. In most cases these cysts rupture and resolve spontaneously. Histopathology: Similar epithelial cysts may occur along the midline of the palate, of new born or (Epstein pearls). No treatment b- Dentigrous Cyst (Follicular cysts) The term "dentigerous" means containing unerupted tooth. The cyst is attached to the neck of the tooth. It represents 15: 17% of all cysts of the jaws. Aetiology and Pathogenesis: It originates through cystic change of the reduced enamel epithelium, after complete formation of enamel of the tooth with accumulation of fluid between the reduced enamel epithelium and the tooth crown.  11 The attachment of the cyst lining at the amelocemental junction. The cause of the development of dentigerous cyst is not known. dentigerous cyst may prevent a tooth from erupting. Expansion of the dentigerous cyst is related to increase in cystic fluid osmolarity as a result of degeneration of desquamated epithelial cells into the cyst lumen. Clinical Features: Age: second and third decades. Sex: More common in males. Site: more in mandibular third molar and maxillary canine Small dentigerous cysts cause no symptoms and may be discovered accidentally. As the cyst grows within bone, it causes both resorption and expansion of bone , facial asymmetry, Displacement of teeth and resorption of roots of adjacent teeth there is usually pain and increased swelling if a dentigerous cyst becomes infected. Radiographic Features: Well defined, unilocular radiolucency in association with the crown of an unerupted tooth.sometimes the radiolucent area is surrounded by a thin sclerotic line Most commonly the cyst is central Also the cyst may develop with only one side of the crown (Lateral dentigerous cyst)  12 Long-standing dentigerous cysts extending toward the roots of adjacent erupted teeth, root resorption has been noted Histopathologic Features: The cyst is lined by a thin regular non- keratinized stratified squamous epithelium attached to the tooth at the cementoenamel junction in an uninflamed cyst the epithelial lining is about 2-4 cell layers thick. In maxillary cysts ciliated epithelium may be seen The connective tissue wall of the cyst is : Inflammatory cells are absent. cholesterol cleft foreign body giant cells. When inflammation occures : epithelial hyperplasia and inflammatory cells. Cyst Contents: Yellowish fluid cholesterol crystals, if the cyst is acutely infected the fluid may be purulent Differential Diagnosis: 1- Unilocular ameloblastoma. 2- Adenomatoid odontogenic tumour. 3 Ameloblastic fibroma. Treatment: 1- Removal of the associated tooth and enucleation of the cyst. 2- Very large cysts of the mandible may need marsupialization to allow shrinkage of the bony defect.  13 Complications: 1- Transformation into an ameloblasloma. 2- Carcinomatous transformation. 3- Destruction of a large area of the jaw with possible fracture. Eruption Cyst: Uncommon superficial dentigerous cyst occurring in the soft tissue of the gum or alveolar mucosa over a tooth about to erupt. Clinically: Age: Children deciduous teeth or permanent molars Site: Gum overlying the unerupted tooth. Shape: Soft rounded swelling if blood is present in the cystic space, the swelling appears deep blue & hence the term "eruption haematoma". Treatment: Not needed because during tooth eruption cyst will disappear spontaneously,. C- Odontogenic Keratocyst (Primordial Cyst) Aetiology and Pathogenesis: it arises from cystic degeneration of enamel organ before tooth formation. Cyst which arises in an area without any missing teeth develop from supernumerary tooth germs Clinical Features:  14 Least common type of odontogenic cyst 7% Age: Second and third decades. Sex: No sex predilection. Site: Common in the mandible and maxillary third molar followed by the canine region. Usually remain symptomless unless If it becomes infected it may produce paraesthesia of the lower lip, pain and swelling of the jaws displacement of teeth of the involved area Radiographic Features: The unilocular lesions are well circumscribed radiolucency with smooth margins and thin radiopaque borders Multilocular primordial cyst can be distinguished from ameloblastoma. Cyst Contents: Keratocysts contain keratin seen during operation as dirty white or yellowish material which has an appearance similar to pus but without an offensive smell. Histopathologic Features: Epithelial lining is a thin, regular, stratified squamous epithelium , smooth basement membrane. The basal cells are columnar palisaded with intensely stained nuclei, Parakeratotic type : high recurrence rate of a bout 40%. Orthokeratotic type : less aggressive ( much lower recurrence rate)  15 Primordial Cyst Parakeratotic type high recurrence rate Histologic Variations of the: Parakeratinized Keratocyst: 1- Budding of the basal layer into the underlying connective tissue, 2- Daughter cysts within the connective tissue wall of the cyst,. Reasons of recurrence are: 1- Thin epithelial lining may fragment and may be partially retained. 2- daughter cysts may be left behind in the bone after operation. Diff. Diagnosis: 1- amelobastoma. 2- central giant cell granuloma 2- NON-ODONTOGENIC CYSTS a- Nasopalatine canal ( tract ) cysts: 1- Incisive canal cyst: That may be located within the nasopalatine canal Etiology: This canal joins the nasal and the oral cavities epithelial remnants of embryonic nasopalatine ducts within the incisive canal. Bacterial infection or trauma stimulates epithelial remnants to proliferate.( cyst formation ) Clinical Features: Nasopalatine cyst is less than 1% of all cysts of the oral cavity.  16 Age: between 40y. and 60 y. Sex: Males are affected more commonly. Site: Any point along the incisive canal. Size: size of the nasopalatine duct cysts are between 0.6 and 1.5 cm and do not exceed 2 cm in diameter. If they become infected, may cause a rapid swelling radiating pain. A salty taste, numbness of the anterior aspect of the palate and sensation of fullness. The adjacent incisors are vital Radiographic Features: Symptomless, discovered in routine x-ray examination. round ovoid or heart-shaped radiolucency, in the midline between the roots of the maxillary central incisors. The size of the incisive foramen, however, not exceed 6 mm in diameter. Histopathologic Features: The cyst is lined by : stratified squamous epithelium, in its oral portion pseudostratified ciliated columnar epithelium nasal portion any combination of these. The connective tissue wall of the cyst shows  17 1- mucous glands 2- large blood vessels. 3- Nerve trunks 4- inflammatory cell infiltration and 5- Cholesterol clefts are uncommonly seen. Cyst Contents: Viscous fluid content …mucoid or pus if the cyst has been infected. 2- Cyst of the Palatine Papilla: Develops from the epithelial remnants in the palatine papilla. The mucosal covering of the papilla is normal, superficial fluctuant bluish swelling appears just behind it, ruptures spontaneously with a discharge of salty fluid, x-ray is negative. b- Fissural Cysts (Inclusion Cysts) Arise from epithelium entrapped in the lines effusion of embryonic processes: a- Globulomaxillary cyst. b- Nasolabial cyst. c- Median palatal cyst. d-Median mandibular cyst. a- Globulomaxillary cyst.  18 Etiology : it is considered to arise from non odontogenic epithelial This is a cyst found between the maxillary lateral incisor and canine teeth arising from non-odontogenic epithelium entrapped at the site of fusion of the globular and maxillary process. Radiographic Features: Well defined radiolucency, producing divergence of the roots of the maxillary lateral incisor and canine teeth. Histopathologic Features: Cysts are lined by embryonic cuboidal epithelium or ciliated columnar or transitional epithelium. The connective tissue is free from inflammatory cells. b-NASOLABIAL CYST It is a soft tissue cyst and does not involve the alveolus. Aetiology and pathogenesis: it is considered to arise from epithelial entrapment at the site of fusion between the lateral nasal and maxillary processes.. Clinical Features: Age: Fourth and fifth decades. Sex: More in females 4:1.  19 Soft tissue swelling of the upper lip in the canine region that obliterates the nasolabial fold, mild nasal obstruction. The cyst may extend intraorally in the mucolabial fold, grow at a slow rat Radiographic Features: Negative in x-ray but bone resorption may result from pressure along the labial aspect of the anterior maxilla. c- MEDIAN PALATAL CYST Epithelial remnants at the line of fusion of the palatal processes or a posteriorly displaced nasopalatine cyst. d- MEDIAN MANDIBULAR CYST It arises from epithelial entrapment in the midline of the mandible during fusion of the two mandibular arches. 3- PSEUDOCYSTS a-Traumatic bone cyst The traumatic bone cyst is a bony cavity with no epithelial lining and often no fluid content. Pathogenesis:  20 The pathogenesis of this cyst is not clear although most believe that it is associated with mild trauma to the jaw that causes bleeding and haematoma formation within bone. it breaks down leaving an empty cavity within the bone. Steady expansion of the lesion occurs until cortical bone is reached. About 80% of patients gave history of prior trauma to the area of involvement. Clinical Features: Age: Below 40 years of age. Site: mandible body and ramus. Most commen molar premolar region symptomless and may be discovered accidentally on routine radiography. The lesion does not cause expansion of the cortical bone in most cases; Pain is uncommon. Teeth associated with the cyst often vital and not loosened. Radiographic Features: The cyst varies in size and may extend from the body of the mandible into the ramus. It is located above the inferior alveolar canal, and appears as a well demarcated unilocular cavity the cyst may project upwards and produce a scalloped contour between the roots of the teeth. In the anterior region, the outline is usually , round or oval in shape adjacent teeth are vital ,but may be displaced , Lamina dura of roots is intact  21 Histopathology: The cyst cavity may contain remnants of blood or blood-stained fluid, the lining is thin fibrous or granulation tissue with' no epithelial component. Treatment and Prognosis: The cavity is opened surgically, irrigated with saline, the walls' are then scratched to establish bleeding into the lesion prior to closure, bone repair will occur with no recurrence. b- ANEURYSMRL BONE CYST It is classified as a pseudocyst because it appears radiographically as a cyst-like lesion but microscopically exhibits no epithelial lining. Aetiology and Pathogenesis: Although the pathogenesis of aneurysmal bone cyst is unknown. one suggested view is increased venous pressure, dilated vascular bed in the bone area. Resorption of bone by giant cells then replaced by connective tissue, osteoid and new bone. Clinically: Age: under 30 years of age (Second decade). Sex: Slight female predilection. Site: the jaws molar areas.  22 Appearance: Firm swelling ,…often painful and tender. At operation, excessive bleeding ….resembling a blood-soaked sponge. Radiographic Features: There is multilocular radiolucency with a honeycomb or soap- bubble appearance. Subperiosteal new bone deposition teeth may be displaced with or without root resorption. Histopathologic Features: Fibrous connective tissue , many blood-filled spaces. extravasated red blood cells , haemosiderin histiocytes, large multinucleated giant cells. New osteoid tissue and thin bone areas Treatment: curettage or excision. c- STATIC BONE CYST (Developmental mandibular salivary gland depressio This is not a true cyst as it has no epithelial lining, but appears cystic or radiolucent area on radiographic examination. It is caused by a developmental inclusion of sub-mandibular salivary tissue within or adjacent to the lingual surface of the body of the mandible. The lesion is entirely asymptomatic and may be discovered accidentally upon x-ray examination.  23 Radio-graphically: It appears round to ovoid, sharply circumscribed radiolucency situated beneath the level of the inferior dental canal. The lesion is constant in size To confirm diagnosis a sialogram is made where a radiopaque material is injected into the duct of the sub-mandibular gland of the affected side, the presence of salivary tissue in the cyst can be detected. Treatment: Once diagnosed, no treatment is required. 4-SOFT TISSUE CYSTS OF JAWS AND NECK a- Dermoied and Epidermoied cysts Pathogenesis: This developmental cyst is derived from epithelial debris in the midline during closure of mandibular arches. Clinical Features: Age: Young adults. Sex: No sex predilection.  24 Site: Anterior part of the floor of the mouth, sub-mandibular and sub lingual areas. Appearance: When located above the mylohyoid muscle it produces a bulge in the floor of the mouth, causing elevation of the tongue causing difficulty in eating and drinking. When the cyst is deeper, it causes bulging in the submental area. The cyst is painless, lowly growing and varies in size from less than 2 cm in diameter to several centimeters. The consistency of the cyst varies from soft to fluctuant.. The cyst may have a doughy consistency on palpation. Histologic Features: thin layer of keratinized stratified squamous epithelium. The lumen is filled with keratin. These cysts are called "epidermoid cysts". In other cases numerous sebaceous glands, hair follicles and teeth. This lesion is called dermoid cyst Treatment: Surgical removal. b-THYROGLOSSAL TRACT CYST Most common developmental cyst of the neck 75% of neck cysts. Aetiology and Pathogenesis:  25 In the fourth week I.U. life at the foramen caecum, the thyroid starts to develop by downward growth of epithelium through the base of the tongue to midline of the neck. Then the tract breaks up but residual epithelial elements may persist and proliferate to form a cyst. The cause of proliferation of the remnants is not known. Clinical Features: Age: at any age. Appearance: Slowly growing asymptomatic firm cystic midline mass varies in size from a few millimeters to several centimeters. Site: Any where. It may occur in the floor of the mouth. within the tongue near the foramen calcium, if large, may cause dysphasia or interfere with eating and speech they move or swallowing, if the cyst becomes infected drainage as sinus tract may occur and an opening on the skin Histopathologic Features: the cyst lining varies depending upon its location above the level of the hyoid bone ….stratified squamous epithelial below the level of the hyoid..ciliated or columnar type epithelium. The connective tissue wall contain areas of thyroid tissue, lymphoid tissue and mucous glands.  26 Treatment: Complete surgical excision is recommended. C- BENIGN CERVICAL LYMPHO-EPITHEUAL CYST (Branchial cleft cyst, Benign cystic lymph node) It is located on the lateral aspect of the neck, anterior to the sternomastoid muscle. Pathogenesis: The origin of this cyst is from remnants of epithelial cells of branchial grooves. entrapped in cervical lymph nodes that develop in this area. Clinical Features: Age: Childhood and young adults. Asymptomatic movable mass on the lateral aspect of the neck close to the anterior border of sternomastoid muscle. Slowly growing if the cyst becomes 'infected, abscess and draining sinuses may form this cyst may occur at angle of the mandible, Histopathologic Features: The cyst is usually lined by stratified squamous epithelium, but may contain areas of pseudostratified columnar epithelium. The wall of the cyst is generally lymphoid tissue with a typical lymph node pattern showing well-formed germinal centers.  27 Treatment: Surgical excision. d- MUCOUS EXTRAVASATION CYST Mucocele, mucous extravasation cyst and ranula etiology and Pathogenesis: Mechanical trauma to the minor salivary gland excretory duct as biting the lip or check resulting in injury. This results in pooling of mucous into the surrounding connective tissue stroma. The pool of extravasated mucous induces an inflammatory reaction in the surrounding connective tissue, with polymorphnuclear leucocytes, macrophage granulation tissue response resulting in the formation of a wall around the mucin pool, giving a pseudocyst appearance. Clinical Features: Age: Children and young adults. Site: mucocele and extravasated cyst is : the lower lip, buccal mucosa Site: of Ranula is : ventral surface of the tongue, floor of the mouth. Appearance: soft painless swelling with smooth surface showing translucency. They range from a few millimeters to a few centimeters diameter if aspiration is attempted, decrease in size. Histopathologic Features:  28 Mucocele, Mucous extravasation cyst : The mucin pool is surrounded by compressed fibrous and granulation tissue infiltrated by large numbers of neutrophils, macrophages, lymphocytes and occasionally plasma cells. The adjacent salivary elements, show acinic degeneration and ductal dilatation. Treatment: Surgical excision.