Definition: Cyst is a pathological fluid field cavity lined by epithelium. (Ref: Cawson)

OrCyst is pathological fluid field cavity lined by epithelium. The

epithelium itself is surrounded by fibrocartilagenous connective tissue and may be derived from various sources.

OrCyst is a cavity occurring in either hard or soft tissue with a liquid,

semisolid or air content. It is surrounded by a definite connective tissue wall or capsule and usually has an epithelial lining.

(Ref: Kruger)

Cyst contents: Cyst fluid contains-

1. Largely inflammatory exudates with high concentration of proteins

2. High molecular weight, breakdown products of RBC(Cholesterol Crystal)

3. Exfoliated epithelial cells4. Fibrin

Sometimes cysts are believed to contain gas. Example-Cyst of the intestinal wall such as pneumatosis cystoids intestinalis.

(Ref: Kruger)

Classification: A. Congenital Cyst-

i. Thyroglossal cystii. Dermoid and Epidermoid cyst

iii. Branchiogenic Cyst

B. Developmental cyst- Odontogenic cyst:

a. Periodontal cyst- Gingival cyst Lateral cyst Periapical cyst Residual cyst

b. Follicular cyst or premordial cystc. Dentigerous or erruption cyst

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Central type Lateral type Circumferential type Multiple type

d. Keratocyst

Non odontogenic cysts- Fissural type

Incisive canal Nasoalveolar Globulomaxillary cyst Median cyst

Retention type Mucocele Ranula

C. Haemmorrhagic or traumatic bone cyst or cyst without epithelial lining or Pseudocyst:

Solitary bone cystAneurysmal bone cyst

D. Neoplastic varitey: Ameloblastoma

Cyst like lesions:1. Tumors of the soft tissues that may have a clinical appearance of cyst-

Fibroma Lipoma Myxoma Papilloma Haemangioma Lympgangioma

2. Lesion presenting a radiolucent appearance simulating a cyst- Ameloblastoma Giant cell tumor Fibrous dysplasia Metastatic carcinoma Ostelytic sarcoma Mulyple myolema Ossifying fibroma

3. Metabolic or systemic dysfunction that may give rise to lesions of cystic appearance-

Hyperparathyroidism Histocytosis-X (Disease of reticoendothelial cell)

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4. Larval forms of various worms like tape worm frame cystic cavities in the muscles in the body. (Ref: Kruger)

Common clinical Features of Cysts:

It is often symptom less until infected. Noticeable during radiological investigation and form sharply

define radiolucencies with smooth border. Grow slowly and expensively, displacing rather than resorbing

teeth. Swelling is usually bony, smooth but later soft & fluctuant. Evidence of case of missing or non vital teeth. Fluid may be aspirated & thin walled cyst may be transilluminated. Rarely large enough to cause pathological fracture. Appear bluish when close to the mucosal surface.

Fluid characteristics of some cysts

Relative frequency of different types of jaw cysts

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Cyst FrequencyRadicular 65-75%

Dentigerous 15-18%Keratocyst 3-5%

Nasopalatine 5-10%Lateral periodontal <1%

Paradentral <1%

Mechanism of formation or pathogenesis of cyst (periodontal):

1) Proliferation of epithelial lining & fibrous capsule.2) Hydrostatic pressure of cystic fluid.3) Resorption of surrounding bone.

Pathogenesis is given below: If dental caries is untreated at extends & involves pulp causes

hypermea of pulp. Pulp necrosis occurs & infection gradually extends through the

pulp canal & reaches to the apical region & then to the Periapical tissues.

Periapical periodontitis & acute or chronic inflammatory lesion persist.

Gradually granuloma is formed due to localization & neutralization of inflammation by the healthy surrounding tissue

Epithelial cell rest of malassez adjacent to granuloma is stimulated.

Epithelium covers the whole granuloma. The central cell can’t get blood supply. Liquefactions necrosis of central tissue occur due to ischemia &

also due to compression of surrounding capillaries. Cavity formation occurs & lined by epithelium. It starts

behaving as a semi permeable membrane. This membrane allow fluid to pass into the cavity & not out of

cavity. This accumulation of intra cystic fluid accounts for an increased

hydrostatic pressure & attracts more fluid because of an increased osmotic pressure.

It puts pressure on the adjacent structure specially bone. Cystic tissue release bone resorbing factors such as

prostaglandins E2 & E3, collagenase & two cytokines, like interlinking 1&6 which causes Resorption of surrounding bone.

4

Ultimately the cyst resorbs all the layer of cortical bone & then the cyst is seen from outside the jaw as a fluctuant swelling beneath the mucous membrane, which is bluish in colour.

Developmental cyst (Odontogenic)

Radicular Cyst/Periodontal cystIt is an inflammatory cyst which results due to infection extending

from the pulp into surrounding periapical tissues. It may develop apically, when it is termed as Periapical radicular cyst or it may develop on the side of the root of pulp less tooth, when it is termed as a lateral periodontal Radicular cyst.

Incidence:

The most common of all cyst of odontogenic origin. Male are affected more commonly than females. Very few cases are seen in the 1st decades, peak incidence is in the 3rd & 4th decades.

Site: The maxilla is affected more than 3 times as frequently as the

mandible.

Clinical features: 1. Slowly progressive, painless swelling with no symptoms until they

become large enough.2. If infection occur, the swelling becomes painful & may rapidly

expand, partly due to inflammatory oedema.3. At first the swelling is rounded and hard.4. Later when the bone has been reduced to eggshell thickness, a

crackling sensation may be felt on pressure.5. Finally part of the wall resorbed entirely away, leaving a soft

fluctuant swelling, bluish in colour, beneath the mucous membrane.

6. The involved tooth or teeth will be found non vital, discolored, fractured or heavy restoration or a failed root canal.

7. The involved tooth or teeth may be found sensitive on percussion or hyper mobile or displace.

5

Radiological Features: Well defined radiolucent area at the apex of the tooth. It may also have a thin radio opaque border. In case of very

large cyst or infected cyst, the radio opaque border is absent. Root resorption is rare but may be seen. Radiograph of the involved tooth may reveal deep restoration,

extensive caries, fracture etc. Involve tooth is always non vital.

Histopathological Features: Lining:

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Fig: Clinical appearance of a radicular cyst in the right maxillary alveolar

process.

Fig: Radicular cyst associated with grossly carious and non-vital first

permanent molar.

i. It is lined by nonkeratinised stratified squamous epithelium.

ii. Define basal cell layer is absent.iii. Epithelial layer is thick, irregular & hyperplasic or net

like.iv. Occasionally inflammatory cysts contain Hyaline bodies.

Cyst capsule and wall:i. It is formed by fibrous connective tissue.

ii. It contains inflammatory cells.iii. Cholesterol clefts are found.iv. Around the cleft, multinucleated giant cells are present.

Cyst cavity:i. Protein rich fluid is found.

ii. Broken down leukocyte are present.iii. Foam cells are found.iv. When infected chronic inflammatory cells, granulation

tissues.Russel bodies are found.

Diagnosis: Clinical diagnosis by aspiration Radiological diagnosis Biopsy

Differential diagnosis: 1. Granuloma2. Periapical cementosseous dysplasia3. Solitary bone cyst4. Giant cell granuloma5. Odontogenic Keratocyst6. Periapical Scar7. Nasopalatine duct cyst8. Surgical defects

Treatment: 1. Non vital teeth that are associated with the cyst, can either been

extracted or can be retained by endodontic treatment and apisectomy.

2. Generally radicular cyst is treated by enucleation.3. Incase of large cyst, marsupialization followed by enucleation is

performed.

Dentigerous cyst/ Follicular cyst

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It is a developmental odontogenic cyst that surrounds the crown of an unerrupted or impacted or developing tooth and remain attached to the neck of the tooth at the cemento-enamel junction.

Pathogenesis: This cyst develops after the formation of crown, when the crown is

covered by two layers of reduced enamel epithelium.1. External enamel epithelium2. Internal enamel epithelium

When cystic fluid accumulates between enamel and reduced enamel epithelium, or between external and internal enamel epithelium, gradually a cavity is formed, lined by epithelium and containing fluid and thereby forming the cyst.

Clinical Features: Usually it is symptom less lesion. It occur most often in young individuals. More common in males than females. The most common sites are the mandibular 3rd molar area,

followed by maxillary cuspid area, upper 3rd molars & lower bicuspid area.

Secondary infection of cyst causes pain. Clinically a tooth from normal series, will be found missing.

May be failed to errupt or may be tilted. Usually it is slow growing but may resorbs cortical bone. May produce a bluish fluctuant swelling involving the

overlying alveolar mucosa. If it enlarge greatly, it will produce a deformity of region

involve. Diagnosis:

1. Aspirate

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Fig: Dentigerous cyst, removed together with its associated tooth.

2. Radiological examination3. Histopathological Feature

1. Aspirate: The cyst contents consist of clear yellowish fluid, in which cholesterol crystals may be present.

2. Radiological Feature: Well defined radiolucent area,covering the crown of

involved tooth is common feature. It is rounded and uniloculer. Bony outline is sclerotic. Infected cyst may show ill defined radiolucent border. Affected tooth may be displaced or root resorption may be

seen.3. Histopathological Feature:

o Lining: It is lined by nonkeratinised stratified squamous epithelium. Epithelium lining is very thin (2-3 cell layer). It is devoid of retepeg. Contains mucous cells in the epithelium lining.

o Cyst wall: It is formed by fibrous connective tissue. Usually no inflammatory cells are present. It contains glysaminoglycanes ground substance. Sometimes cholesterol clefts are also present.

o Cyst cavity: Cyst cavity contains fluid which is watery or straw colored.

Differential diagnosis: 1. Calcifying odontogenic cyst

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Fig: Histopathological appearance of a dentigerous

cyst.

2. Radicular cyst3. Unicystic ameloblastoma4. Primordial cyst5. Odontogenic Fibroma

Treatment: Marsupialization:

It is indicated in children if the cyst is very large in size and the involved tooth or teeth are to be maintained. Afterwards orthodontic treatment is indicated.

Enucleation: If extraction is indicated, enucleation of the cyst is done after extraction.

Odontogenic Keratocyst/Primordial Cyst

The term “Keratocyst” was coined by philipsen and was based on the histological appearance of the cystic lining. Now a day there is two variants of keratocyst are identified.

1. Orthokeratinized odontogenic keratocyst2. Para keratinized odontogenic keratocyst

Origin: o Dental lamina or its remnantso Basal cells from overlying mucosao Enamel organ

Incidence: Occur in those aged 7 to 93 years however, the pick incidence is between ages of 20 to 40 years.

Site: The mandible is usually affected more than the maxilla. They can occur anywhere in the jaws, including midline, though majority of the cysts are seen posterior to the first bi-cuspid.

Clinical features:

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a) Keratocyst like other jaw cysts, are asymptomatic until the bone is expanded or they become infected.

b) Spreads extensively along marrow spaces before expanding the jaw.

c) Males are more affected than females.d) The enlarging cyst may lead to displacement of the teeth,

percussion of the teeth overlying the cyst may produce a dull or hollow sound.

e) There may be present of swelling, pain, trismus, neuromuscular bundle deficits.

f) If acute infection sets in, with accumulation of pus within the sac, neuropraxia of the nerve results with the onset of labial paraesthesia or anaesthesia.

g) When tension is relieved, by a sinus tract or surgical drainage, sensation returns to normal.

Radiological features: The keratocyst may be unilocular or multiolocular, well defined

radiolucent area, either more or less rounded with a scalloped margin.

May or may not associate with unerrupted tooth. Roots of adjacent tooth may become displaced.

Histological features: Cysts are thin walled and are lined by a uniform keratinized

stratified squamous epithelium, which is usually 5 to 8 cell layers thick and is devoid of retepegs.

Cyst lining typically much folded.

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Fig: Radiology of odontogenic keratocyst showing multi-locular

The keratin formed by the epithelium is seen in two variants. They are-

a) Parakeratin- in which there is persistence of the nuclei.b) Orthokeratin- in which the nuclei are absent.

Clearly defined basal layer of the tall cells in parakertinized cyst. Epithelial lining is weakly attached to the fibrous wall.

Cystic contents (aspirate): Odontogenic keratocyst contain a dirty white, viscoid suspension

of keratin, which has an appearance of pus, but without an offensive smell.

Differential diagnosis: Ameloblastoma Dentigerous cyst Radicular cyst Lateral periodontal cyst Globulomaxillary cyst Primordial cyst

Treatment: a) Small single cyst with regular spherical outline- enucleated from an

intraoral approach.b) Large or less accessible cysts with regular spherical outline-

It is enucleated from an extra oral approach. Care should be taken to ensure that all fragments of the extremely thin lining are removed.

c) Unilocular lesions with scalloped or loculated periphery and small multilocular lesions- treated by marginal excision in example

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A

Fig: Histological feature of odontogenic keratocyst. A) Folding of the epithelium from the connective tissue. B) A thick layer of keratin at

B

resection of the containing block of bone, while maintaining the continuity of the posterior and inferior borders as in the ascending ramus, angle and body of the mandible. If it is adherent to the overlying oral mucosa or muscle then it should be excised along with marginal excision.

d) Large multilocular lesions with or without cortical perforation-Resection of the involved bone followed by primary of secondary reconstruction with stainless steel, vitallium, titanium etc. and with various bone grafting procedure. Carnoy’s solution improves the results of the enucleation.

Recurrence: Frequently recur after enucleation. Recurrence rate up to 5 to 62.5%.

Gingival cyst

Type: 1) Dental lamina cyst of newborn (Bohn’s nodules)2) Gingival cyst of adults

Dental lamina cysts of newborn (Bohn’s nodules) Upto 80% of newborn infants have small nodules or cyst in the

gingiva, due to proliferation of the epithelial rest of Serres. Most resolve spontaneously. Cyst may also arise from non-odontogenic epithelium along the mid palatine raphe. These may enlarge sufficiently to appear as creamy colored swellings a few mili meters in diameter, but also resolve spontaneously in a matter of months.

Gingival cysts of adults

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Gingival cysts are exceedingly rare. They usually from after the age of approximately 40. Clinically, they form dome shaped swellings less than 1cm in diameter and sometimes erode the underlying bone. They are lined by very thin, flat, stratified squamous epithelium and may contain fluid or layers of keratin. They are unlikely to recur after enucleation.

Fig: Gingival cyst of newborn (Bohn’s nodules).

Lateral periodontal cystThese uncommon intra-osseous cysts are developmental and form

beside a vital tooth. These cysts appear to arise in intimate association with the lateral root surface of an erupted tooth with a predilection for the mandibular bicuspid area.

Clinical features: It is an intra-osseous cyst from beside a vital tooth. It is symptom less unless around the bone to extend into gingival. It affects the mandibular premolar to canine region

(bicuspid/cuspid/incisor area). Age- 22-85 years but mean is 50 years. It rarely affects the maxillary lateral incisor area. It sign and symptom is bound in clinically. Only seen in routine

radiographic examination of teeth. If cyst is located on the labial surface of the root, there may be a

slight mass obvious although the overlying mucosa is normal. If cyst becomes infected, it may resemble a lateral periodontal

abscess and even seek to establish drainage. Diagnosis:

Radiological features: A radiolucent area in apposition to the lateral surface of a tooth

root. The lesion is usually small (seldom over 1cm in diameter). It may or may not be well circumscribed. Border is definitive and even surrounded sometimes by a thin layer

of sclerotic bone.

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Fig: Gingival cyst of adult.

Histological features: It is lined by non-keratinized stratified squamous epithelium. Cuboidal or even columnar cells may be found composing the

lining. The lining is flat and only one or two cells thick but sometime with

focal thickness. Many of the lining cells have a clear, vacuolated glycogen rich

cytoplasm.

Treatment: Enucleation is the treatment of choice. Related tooth can be retained if healthy.

Type: 1. Botryoid odontogenic cyst2. Glandular odontogenic cyst

Haemmorrhagic or traumatic bone cyst or cyst without epithelial lining

or Pseudocyst

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Fig: Radiology of a lateral periodontal cyst in between the roots of lateral incisors and

canine.

Solitary bone cyst

Other names- simple bone cyst, traumatic bone cyst, haemorrhagic bone cyst, idiopathic bone cavity, pseudo cyst etc.

Etiology: A number of theories have been forwarded, these include-

Trauma and haemorrhage with failure of organization. Spontaneous atrophy of the tissue in a central benign giant

cell lesion. Abnormal calcium metabolism. Chronic low grade infection. Necrosis of fatty narrow secondary to ischaemia. Aberration in the development and the growth of the local

osseous tissue.

Clinical features: Incidence: mostly seen in teenagers and are uncommon after the

age of 25. Mandible is mainly affected, majority are seen in the subapical

region, above the inferior dental canal, in the cuspid and molar region.

Females are affected more than the males. Usually symptom less and found during routine dental

examinations. Rarely does it become painful. It may cause jaw expansion rather than erosion. The associated teeth are vital. Unerrupted teeth usually molars, may be prevented from eruption.

Radiological features: A rounded uniloculer radiolucent area with ill defined margin. The area of radiolucency is typically much larger than the size of

the swelling suggests. The roots of related teeth may be displaced, lamina dura is intact,

and resorption is not seen. Associated tooth is vital.

Histopathology: 1. Cyst wall- avascular connective tissue membrane is seen.2. Cavity wall-

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Usually empty. No visible lining is usually seen, sometimes a thin membrane, granulation tissue or blood clot may be found.

Loose vascular fibrous tissue membrane with hemosiderin pigment may be seen with small multinucleated cells.

Cystic contents: A deep yellow colored fluid may be obtained. This contains plasma

proteins. Some cyst remains empty. They may contain gas such as nitrogen, oxygen and carbon dioxide.

Differential diagnosis: Cemento-osseous dysplasia Fibro osseous proliferation Radicular cyst

Treatment: a) These lesions may resolve spontaneously.b) Gentle curettage is the choice of treatment which stimulates

haemorrhages which results in rapid obliteration of the defect and eventual healing by new bone formation.

Technique: i. Preparation of the surgical fluid with antiseptic solution.

ii. Flap design is made.iii. Application of local aneasthesia.iv. Incision is made over the mucosa of the affected area according to

flap design.v. Intraosseous window is made with bur and Rongeur forcep.

vi. The bone may show shiny and smooth appearance, but still it is to be curetted.

vii. Proper irrigation is needed to make the cavity clean.viii. Closure of the wound is performed by giving suture.

Aneurysmal bone cystThey are vascular malformations and rare in the jaws.

Etiology:

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o History of the traumao Possible relationship with the giant cell lesiono Variation in the haemodynamics of the area o Sudden venous occlusion

Incidence: It is usually seen between 10 to 20 years of age. There is no sex

variation. It is rare in the jaws.

Site: Jaw lesions are usually in the mandible.

Clinical features: The lesions produce firm swellings. The patient may give a history of rapid enlargement. The teeth may show displacement. The affected tooth remains vital. Egg shell cracking may be exhibited.

Radiological features: Radiologically they are unilocular, oval or spherical radiolucent

area. They show ballooning of the corted. Sometimes may give a multilocular appearance seem honey comb

or soap-bubble appearance. They generally show a subperiosteal layer of the new bone. Tooth may be displaced and root resorption may be described.

Histopathological features: They are consists of numerous blood filled spaces in a fibrous

connective tissue stroma. Small multinucleated cells and scattered trabeculae of woven bone

may be seen. May contain large number of multinucleated giant cells,

fibroblasts, haemorrhage and hemosiderin.

Cystic contents (aspirate): Dark venous blood can be aspirated.

Differential diagnosis: Fibrous dysplasia

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Ossifying fibroma Giant cell granuloma

Treatment: a. Thorough curettage which may need to be repeated as the lesion

occasionally recurs.b. Local excision with bone grafting has been suggested in very large

lesions.

Non-odontogenic cysts (fissural or midline cysts)

Name of some midline cysts are: Naso-palatine cyst/ palatine papilla cyst Incisive canal cyst Median palatine cyst Median alveolar cyst

Naso-palatine duct cyst

Clinical features: It is slow growing. Form is the incisive canal region. Asymptomatic in nature. When the cyst becomes longer it causes swelling in the midline of

the anterior palate. They are usually symmetrical but may be slightly longer to one

side. The long spheno-palatine and vessels may be present in the wall. Occasionally they cause intermittent discharge with a salty taste. The anterior palatine fossa must be distinguished from a small

nasopalatine cyst.

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Diagnosis:

Radiological features: Radiologically shows a rounded radiolucent area with a well

defined sclerotic margin. Occasionally appear heart shaped because of radiographic

superimposition of nasal spine.

Histological features: It is lined by stratified squamous epithelium, pseudostratified

ciliated columnar epithelium, cuboidal epithelium or any combination of these.

The connective tissue wall of this cyst frequently shows inflammatory cell infiltration.

Collections of mucous glands are often present as well as several large blood vessels and nerves.

Treatment: Enucleation.

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Fig: Typical features of a nasopalatine cyst.

Fig: Rounded radiolucency of a nasopalatine cyst.

Naso-labial cystThe naso labial cyst is not fount within bone, but is usually

described as a rare fissural cyst that may involve bone secondarily. It has been thought to arise at the junction of the globular process, the lateral nasal process and the maxillary process as a result of proliferation of entrapped epithelium along the fusion line.

Clinical features: Age- 12-75 years but mean age is 41-46 years. It forms outside the bone in the soft tissue deep to the naso labial

bone. It arises from remnant of the naso lacrimal duct. The cyst may cause a swelling in the fold as well as in the floor of

the nose, being located near the attachment of the ala over the maxilla.

Histological features: It is lined by pseudostratified columnar epithelium which is sometimes ciliated often with goblet cells on by stratified squamous epithelium.

Treatment: The cyst should be surgically excised although care must be exercised to prevent perforation and collapse of the lesion.

Median palatine cystThe median palatine cyst arises from epithelium entrapped along

the line of fusion of the palatal process of maxilla.

Clinical features: It is located in the midline of the hard palate between the lateral

palatine processes. It may become large over a prolonged period of time and produce a

definite palatal swelling. The cause of epithelial proliferation and subsequent cyst formation

is unknown.

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Diagnosis:

Radiological features: A well circumscribed radiolucent area is seen opposite the bicuspid

and molar region. Frequently bordered by a sclerotic layer of bone.

Histological features: Cyst is lined by stratified squamous epithelium overlying a

relatively dense fibrous connective tissue band which show chronic inflammatory cell infiltration.

Sometime it is lined by pseudostratified ciliated columnar epithelium.

Treatment: The treatment as for most of the fissural cyst is surgical removal and thorough curettage.

Congenital cysts

Thyroglossal duct cyst

Thyroglossal duct runs from foramen caecum in tongue to thyroid gland. The cyst arise from any portion of this duct.

Incidence: Highest incidence in infancy and in the second decade. There is no

sex predilection.

Site: It can occur anywhere in the midline along the course of the

embryonic thyroglossal duct. Commonest site is the floor of the mouth.

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Clinical features: 1. Swellings are seen in the midline which are symptom less or may

cause pressure symptoms.2. On palpation swellings are soft, tender and movable.3. At times they may cause dysphagia, dysphoria, or dyspnoea. 4. The size may 1 to 5 cm in diameter.5. Due to infection a sinus tract may develop.

Histopathology: Cyst present above the level of the hyoid bone is lined by stratified

squamous epithelium while these present below the hyoid bone are lined by ciliated columnar epithelium.

In the fibrous wall, lymphoid tissue, thyroid tissue or mucous glands may be seen.

Treatment: o Complete surgical excision of the cyst along with its tract.o Owing to its proximity to the hyoid bone, a central part of the

hyoid bone, approximately 1 to 2 cm may be re to be removed during surgery.

Complications of cystic lesions: Pathological fracture may occur. Infection prior to surgery may acute or chronic. Loss of vitality of teeth. Recurrence in some cysts. Dysplastic, neoplastic or even malignant changes.

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Fig: Thyroglossal duct cyst.

Post operative complications: Oedema or post operative swelling Infection Hematoma formation Neural injuries Oroantral fistula Oronasal opening Fracture of the bone

Dermoid and epidermoid cyst

The dermoid cyst is a form of cystic teratoma, which is lined by epithelium and in addition reveals the presence of skin appendages, e.g.- hair, sebaceous gland or teeth.The epidermoid cyst is also lined by epithelium but does not contain any skin appendages.

Incidence: Mainly occurs in young adolescents. There is no sex predilection.

Site: Midline in the floor of the mouth above or below the geniohyoid

muscle, hard and soft palate, dorsum of the tongue.

Pathogenesis: They are non odontogenic developmental cyst arises from

epithelial rests persisting in the midline after fusion of the mandible and hyoid branchial arches. It is formed by the combination of ectoderm, mesoderm, and endoderm.

Clinical features: 1. Swelling in the midline, floor of the mouth and neck.2. Tongue may elevate due to swelling and causes difficulty in

mastication and speech.3. They are filled with disquamated keratin, giving them a semisolid,

putty like consistency.4. When they are superficial they appear bluish.5. They are usually symptom less until large enough.

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Radiological features: o Unilocular rounded radiolucent area.o Sometime radio-opaque appearance in the center point due to

contains of radio-opaque objects (teeth fragments).

Histopathology: Lined by keratinizing stratified squamous epithelium and contain

keratin scales. Presence of dermal appendages in the wall such as sebaceous

glands, sweat glands, hair follicles etc.

Aspirate: Yellow cheesy material

Treatment: Surgical excision of entire cyst.

Branchial cleft cystBranchial arch remnants can give rise to branchial cyst.

Incidence:

May occur at all ages but frequency seen in between age of 20 to 40 years of age. There is no sex predilection.

Site: The most common location is at the angle of the mandible anterior

to the sternocleidomastoid muscle or the parotid region. Less common in floor of the mouth and ventral surface of tongue. Clinical features:

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Fig: Sublingual dermoid cyst.

1) Size- varies in size but may reach up to 10 cm.2) They are seen as a soft, fluctuant mass.3) Some may develop a fistulous tract and drain externally.4) The intraoral cysts are submucosal and freely mobile.

Histopathology: The cervical cysts are lined by ciliated or non ciliated,

pseudostratified columnar epithelium. It contains goblet cells, lymphocytes. Lumen will contain mucus and desquamated parakeratotic cells. The intraoral cysts are usually lined by stratified squamous

epithelium and lumen contain watery fluid. Lymphoid tissue envelops the cystic lining.

Radiological features: A unilocular radiolucent area with well defined margin.

Treatment: Complete surgical excision.

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Fig: Branchial cleft cyst.

Non-odontogenic cysts (retention or soft tissue cysts)

Mucocele

It is the most common cystic lesion of minor salivary gland. The vast majorities represents extravasation phenomena and have no epithelial lining. The etiology is usually minor trauma. The majority of this lesion is due to damage or rupture of the duct of the minor salivary gland such that mucus can escape in to the tissue. 20% of these lesions may represent true retentions cyst secondary to obstruction or microliths.

Clinical features: Mucocele most often form in the lower lip but occasionally on the

buccal mucosa. Most appear first 3 decades of life. Appear as soft, tense, fluctuant swellings with a blue translucent

color. Usually superficial and rarely larger then 1 cm in diameter.

Histopathology: o The mucous extravasations cyst is composed of pools of mucous

lying in the connective tissue containing numerous inflammatory cysts.

o The wall is composed of granulation tissue with no discernible epithelium lining.

o The mucous retention cyst is lined by a complete layer of duct epithelium. The wall is composed of fibrotic connective tissue.

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Fig: Mucocele, a rounded bluish cyst in lower lip.

Treatment: It should be excised with the underlying minor salivary gland. In case of recurrence CO2 laser can be used to ablate the surgical

bed and any underlying salivary tissue.

Ranula

Ranula is an uncommon type of salivary cyst arising from the sublingual (common) or submandibular salivary glands. The ranula is so named for it’s resemblance to a frog’s belly.The mylohyoid muscle does not always from a complete diaphragm for the floor of the mouth and leakage of saliva below the mylohyoid muscle can allow the lesion to present in the upper neck as a ‘plunging ranula’.

Aetiology: The majority of these lesions result from extravasations of saliva

secondary to trauma.

Clinical features: i. Ranula is a bluish transparent cyst which superficially occurs in the

floor of the mouth beneath the tongue.ii. They are soft, fluctuant and tense swelling.

iii. Sex- females are predominant.iv. Age- between the ages of 10 to 30 years.v. Usually unilateral and 2 to 3 cm in diameter.

vi. They grow slowly and typically painless but may interfere with speech or mastication.

Treatment: Excision of the sublingual gland. Initial treatment through marsupialization.

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Fig: Ranula, large bluish swelling in the floor of the mouth.

A simple incision tends to recurrence and enucleation is difficult because of the very thin wall.

Procedure: i. Initially Wharton’s duct is canulated so that it can be identified and

protected during the dissection.ii. An incision is made slightly medial to and along the long axis of

the sublingual gland.iii. The gland is dissected from anterior to posterior protecting the

submandubular duct (and obtains haemostasis as the dissection proceeds).

iv. Care is taken to identify and preserve the lingual nerve. v. The posterior border of the sublingual gland may be intimately

associated with the oral extension of submandibular gland. Sharp dissection may be required to separate the two glands.

Surgical treatment procedures of cysts

EnucleationThe process by which the total removal of a cystic lesion is

achieved is called enucleation.Enucleation of cyst should be performed with care, in an attempt to remove the cyst in one piece without fragmentation which reduces the chances of recurrence by increasing the likelihood of total removal.

Technique:

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Fig: Enucleation of a dentigerous cyst with a supernumerary tooth.

When extracting teeth with periapical radiolucencies, enucleation via the tooth socket can be readily accomplished using curettage when the cyst is small.With large cyst an incision is made well clear of the margins of the cystic lesion to ensure that the suture line will lie on sound bone postoperatively.A mucoperiosteal flap may be reflected and access to the cyst may be carried out through the labial plate of bone using bone nibblers or a round bar.

Marsupialization/ partsch operation

Indication:

Cyst is very large and where complete enucleation is not possible. If there may be chance of pathological fracture during enucleation. Dentigerous cyst in younger patients where a chance for eruption

of an unerruupted tooth is to be provided. If there may be chances of entering into adjacent paranasal sinus or

nasal cavity during enucleation incase of large cyst. Where there are chances of damages to the neurovascular bundle. If patient cannot undertaken time consuming surgical procedure. When cyst are associated with the crowns of the teeth that the

operator wishes to preserve it.

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Fig: Marsupialization, A) Sutures being placed through mucous membrane and underlying cyst wall. B) Cross section. C) Window cut

Procedure / Technique of Marsupialization: Marsupialization is performed by removing the overlying

mucoperiosteum and bone over the cyst and surface of the cyst lining.

This procedure involves opening up the cyst, draining its contents and exposing the lining epithelium to the oral cavity.

The lining is sutured to the mucous membrane at the margin of the opening.

The cyst cavity can be carefully packed with ribbon gauze soaked in whitehead’s varnish (Iodoform solution) and the packed removed 10-12 days later.

The cavity must be continually repacked as it contracts. Once epithelialization has taken place the pack may be replaced by

a rigid or semi-rigid bung. The healing often takes 6-18 months.

Reference

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Class lectures of Asst. Prof. Dr. Kazi Sazzad Hossain, Head of the department Oral Surgery and Anaesthesiology.

Text book of Oral and Maxillofacial Surgery- Vinod Kapoor.

Text book of Oral and Maxillofacial Surgery- Nilima Anilmalik

Text book of Oral and Maxillofacial Surgery- Gustav O. Kruger.

Essential of Oral Pathology and Oral Medicine-

Cawson and Odell.

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