A ranula usually presents as a translucent blue, dome-shaped, swelling in the tissues of the floor of the mouth. If the lesion is deeper, then there is a greater thickness of tissue separating from the oral cavity and the blue translucent appearance may not be a feature. A ranula can develop into a large lesion many centimeters in diameter, with resultant elevation of the tongue and possibly interfering with swallowing (dysphagia). The swelling is not fixed, may not show blanching and is non-painful unless it becomes secondarily infected. The usual location is usually lateral to the midline, which may be used to help distinguish it from a midline dermoid cyst. A cervical ranula presents as a swelling in the neck, with or without a swelling in the mouth. In common with other mucoceles, ranulas may rupture and then cause recurrent swelling. Ranulas may be asymptomatic, although they can fluctuate rapidly in size, shrinking and swelling, making them hard to detect.

The size of oral mucoceles vary from 1 mm to several centimeters and they usually are slightly transparent with a blue tinge. On palpation, mucoceles may appear fluctuant but can also be firm. Their duration lasts from days to years, and may have recurrent swelling with occasional rupturing of its contents.

The fluid within a ranula has the viscous, jellylike consistency of egg white.

The most common location to find a mucocele is the inner surface of the lower lip. It can also be found on the inner side of the cheek (known as the buccal mucosa), on the anterior ventral tongue, and the floor of the mouth. When found on the floor of the mouth, the mucocele is referred to as a ranula. They are rarely found on the upper lip. As their name suggests they are basically mucus lined cysts and they can also occur in the Paranasal sinuses most commonly the frontal sinuses, the frontoethmoidal region and also in the maxillary sinus. Sphenoid sinus involvement is extremely rare.

When the lumen of the vermiform appendix gets blocked due to any factor, again a mucocele can form.

Signs and symptoms are variable and depend largely upon whether the obstruction of the duct is complete or partial, and how much resultant pressure is created within the gland. The development of infection in the gland also influences the signs and symptoms.

- Pain, which is intermittent, and may suddenly get worse before mealtimes, and then slowly get better (partial obstruction).

- Swelling of the gland, also usually intermittent, often suddenly appearing or increasing before mealtimes, and then slowly going down (partial obstruction).

- Tenderness of the involved gland.

- Palpable hard lump, if the stone is located near the end of the duct. If the stone is near the submandibular duct orifice, the lump may be felt under the tongue.

- Lack of saliva coming from the duct (total obstruction).

- Erythema (redness) of the floor of the mouth (infection).

- Pus discharging from the duct (infection).

- Cervical lymphadenitis (infection).

- Bad Breath.

Rarely, when stones form in the minor salivary glands, there is usually only slight local swelling in the form of a small nodule and tenderness.

The nasopalatine cyst is the most common non-odontogenic cyst of the oral cavity, at an estimated occurrence rate of 73%.

The term is derived from the Greek words "sialon" (saliva) and "lithos" (stone), and the Latin "-iasis" meaning "process" or "morbid condition". A "calculus" (plural "calculi") is a hard, stone-like concretion that forms within an organ or duct inside the body. They are usually made from mineral salts, and other types of calculi include tonsiloliths (tonsil stones) and renal calculi (kidney stones). "Sialolithiasis" refers to the formation of calculi within a salivary gland. If a calculus forms in the duct that drains the saliva from a salivary gland into the mouth, then saliva will be trapped in the gland. This may cause painful swelling and inflammation of the gland. Inflammation of a salivary gland is termed "sialadenitis". Inflammation associated with blockage of the duct is sometimes termed "obstructive sialadenitis". Because saliva is stimulated to flow more with the thought, sight or smell of food, or with chewing, pain and swelling will often get suddenly worse just before and during a meal ("peri-prandial"), and then slowly decrease after eating, this is termed "meal time syndrome". However, calculi are not the only reasons that a salivary gland may become blocked and give rise to the meal time syndrome. Obstructive salivary gland disease, or obstructive sialadenitis, may also occur due to fibromucinous plugs, duct stenosis, foreign bodies, anatomic variations, or malformations of the duct system leading to a mechanical obstruction associated with stasis of saliva in the duct.

Salivary stones may be divided according to which gland they form in. About 85% of stones occur in the submandibular gland, and between 5-10% occur in the parotid gland. In about 0-5% of cases, the sublingual gland or a minor salivary gland is affected. When minor glands are rarely involved, caliculi are more likely in the minor glands of the buccal mucosa and the maxillary labial mucosa. Submandibular stones are further classified as anterior or posterior in relation to an imaginary transverse line drawn between the mandibular first molar teeth. Stones may be radiopaque, i.e. they will show up on conventional radiographs, or radiolucent, where they not be visible on radiographs (although some of their effects on the gland may still be visible). They may also symptomatic or asymptomatic, according to whether they cause any problems or not.

There is a diffuse, gray-white, milky opalescent appearance of the mucosa which usually occurs bilaterally on the buccal mucosa. Less often, the labial mucosa, the palate or the floor of mouth may be affected. The surface of the area is folded, creating a wrinkled, white streaked lesion. Apart from the appearance, the lesion is entirely asymptomatic.

Gingival cyst (or dental lamina 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 whistish bulge. Depending on the ages in which they develop, the cysts are classsfied into gingival cyst of newborn (or infant) 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 formes as a result of cystic degeneration of epithelial rests of the dental lamina (called the rests of Serres).

Gingival cyst was first described by a Czech physician Alois Epstein in 1880. In 1886, a German physician Heinrich Bohn described another type of cyst. Alfred Fromm introduced the classification of gingival cysts in 1967. According to him, gingival cysts of newborns can be further classsified based on their specific origin of the tissues as Epstein’s pearls, Bohn’s nodules and dental lamina cysts.

Nasopalatine duct cysts usually present as asymptomatic palatal swellings, but they may rarely be accompanied by pain and/or purulent discharge. The cysts are generally treated by .

Periapical cysts begin as asymptomatic and progress slowly. Subsequent infection of the cyst causes swelling and pain. Initially, the cyst swells to a round hard protrusion, but later on the body resorbs some of the cyst wall, leaving a softer accumulation of fluid underneath the mucous membrane.

Larger cysts may cause bone expansion or displace roots. Discoloration of the affected tooth may also occur. Patient will present negative results to electric and ice test of the affected tooth but will be sensitive to percussion. Surrounding gingival tissue may experience lymphadenopathy. The alveolar plate may exhibit crepitus when palpated.

Periapical cysts exist in two structurally distinct classes:

Periapical true cysts - cysts containing cavities entirely surrounded in epithelial lining. Resolution of this type of cyst requires surgical treatment such as a cystectomy.

Periapical pocket cysts - epithelium lined cavities that have an opening to the root canal of the affected tooth. Resolution may occur after traditional root canal therapy.

Periapical cysts comprise approximately 75% of the types of cysts found in the oral region. The ratio of individuals diagnosed with periapical cysts is 3:2 male to female, as well as individuals between 20 and 60 years old. Periapical cysts occur worldwide.

Types of Periapical cysts:

Apical: 70%

Lateral: 20%

Residual: 10%

The scalp, ears, back, face, and upper arm, are common sites of sebaceous cysts, though they may occur anywhere on the body except the palms of the hands and soles of the feet. In males a common place for them to develop is the scrotum and chest. They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.

They are generally mobile masses that can consist of:

- Fibrous tissues and fluids,

- A fatty (keratinous) substance that resembles cottage cheese, in which case the cyst may be called "keratin cyst". This material has a characteristic "cheesy" or foot odor smell,

- A somewhat viscous, serosanguineous fluid (containing purulent and bloody material).

The nature of the contents of a sebaceous cyst, and of its surrounding capsule, differs depending on whether the cyst has ever been infected.

With surgery, a cyst can usually be excised in its entirety. Poor surgical technique, or previous infection leading to scarring and tethering of the cyst to the surrounding tissue, may lead to rupture during excision and removal. A completely removed cyst will not recur, though if the patient has a predisposition to cyst formation, further cysts may develop in the same general area.

Gingival cyst of adult is a rare condition. The incidence is less than 0.5%. It is formed from the rests of dental lamina. It is found in the soft tissues on the buccal and labial portions of the jaw. It usually occurs on the facial gingiva as a single small flesh colored swelling, sometimes with a bluish hue due to the cystic fluid. Sometimes, it may occur in cluster, either unilaterally or bilaterally or on the lingual surface of the alveolar process. It is most commonly seen in the canine and premolar regions of the mandible, and are sometimes confused with lateral periodontal cysts. It is not normally problematic, but when it grows larger, it can cause some discomfort. It can be removed by simple surgical excision. They are developed late in life, generally up to the sixth decade of age.

Cysts rarely cause any symptoms, unless they become secondarily infected. The signs depend mostly upon the size and location of the cyst. If the cyst has not expanded beyond the normal anatomical boundaries of the bone, then there will be no palpable lump outside or inside the mouth. The vast majority of cysts expand slowly, and the surrounding bone has time to increase its density around the lesion, which is the body's attempt to isolate the lesion. Cysts that have expanded beyond the normal anatomic boundaries of a bone are still often covered with a thin layer of new bone. At this stage, there may be a sign termed "eggshell cracking", where the thinned cortical plate cracks when pressure is applied. A lump may be felt, which may feel hard if there is still bone covering the cyst, or fluctuant if the cyst has eroded through the bone surrounding it. A cyst may become acutely infected, and discharge into the oral cavity via a sinus. Adjacent teeth may be loosened, tilted or even moved bodily. Rarely, roots of teeth are resorbed, depending upon the type of cyst. The inferior alveolar nerve runs through the mandible and supplies sensation to the lower lip and chin. As most cysts expand slowly, there will be no altered sensation (anesthesia or paraesthesia), since the inferior alveolar canal is harmlessly enveloped or displaced over time. More aggressive cysts, or acute infection of any cyst may cause altered sensation.

Although the treatment of the cyst was previously enuclation of the cyst with removal of the involved tooth or enuclation with root-canal treatment, the current management is enuclation with the preservation of the involved tooth. However, recent evidence suggests self-resolution of this type of cyst, thus close observation with meticulous oral hygiene measures can be employed unless the cyst is infected and symptomatic.

Buccal bifurcation cyst is an inflammatory odontogenic cyst, of the paradental cysts family, that typically appears in the buccal bifurcation region of the mandibular first molars in the second half of the first decade of life. Infected cysts may be associated with pain.

Leukoedema (also spelled leucoedema) is a blue, grey or white appearance of mucosae, particularly the buccal mucosa (the inside of the cheeks); it may also occur on the mucosa of the larynx or vagina. It is a harmless and very common condition. Because it is so common, it has been argued that it may in fact represent a variation of the normal appearance rather than a disease, but empirical evidence suggests that leukoedema is an acquired condition caused by local irritation. It is found more commonly in black skinned people and tobacco users. The term is derived from the Greek words λευκός "leukós", "white" and οἴδημα "oídēma", "swelling".

In the initial phase of the disease, the mucosa feels leathery with palpable fibrotic bands. In the advanced stage the oral mucosa loses its resiliency and becomes blanched and stiff. The disease is believed to begin in the posterior part of the oral cavity and gradually spread outward.

Other features of the disease include:

- Xerostomia

- Recurrent ulceration

- Pain in the ear or deafness

- Nasal intonation of voice

- Restriction of the movement of the soft palate

- A budlike shrunken uvula

- Thinning and stiffening of the lips

- Pigmentation of the oral mucosa

- Dryness of the mouth and burning sensation

- Decreased mouth opening and tongue protrusion

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 (hydrostatic pressure). 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 (the precursor germ layer to skin and mucosa), and so remnants of epithelium can be left in the bone during odontogenesis (tooth development). 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 (also termed cell rests) 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.

Cysts that arise from tissue(s) that would normally develop into teeth are referred to as odontogenic cysts. Other cysts of the jaws are termed non-odontogenic cysts. Non-odontogenic cysts form from tissues other than those involved in tooth development, and consequently may contain structures such as epithelium from the nose. As the cyst grows from hydraulic pressure it causes the bone around it to resorb, and may cause movement of teeth or other vital structures such as nerves and blood vessels, or resorb the roots of teeth. Most cysts do not cause any symptoms, and are discovered on routine dental radiographs.

Some cysts may not require any treatment, but if treatment is required, it usually involves some minor surgery to partially or completely remove the cyst in a one or two-stage procedure.

A Myxoid cyst (also known as a "Digital mucous cyst," and "Mucous cyst") is a cutaneous condition often characterized by nail plate depression and grooves.

About 90% of pilar cysts occur on the scalp, with the remaining sometimes occurring on the face, trunk and extremities. Pilar cysts are significantly more common in females, and a tendency to develop these cysts is often inherited in an autosomal dominant pattern. In most cases, multiple pilar cysts appear at once.

Odontogenic cyst are a group of jaw cysts that are formed from tissues involved in odontogenesis (tooth development). 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.

Thyroglossal duct cysts most often present with a palpable asymptomatic midline neck mass above the level of the hyoid bone. The mass on the neck moves during swallowing or on protrusion of the tongue because of its attachment to the tongue via the tract of thyroid descent. Some patients will have neck or throat pain, or dysphagia.

The persistent duct or sinus can promote oral secretions, which may cause cysts to become infected. Up to half of thyroglossal cysts are not diagnosed until adult life. The tract can lie dormant for years or even decades, until some kind of stimulus leads to cystic dilation. Infection can sometimes cause the transient appearance of a mass or enlargement of the cyst, at times with periodic recurrences. Spontaneous drainage may also occur. Differential diagnosis are ectopic thyroid, enlarged lymph nodes, dermoid cysts and goiter.

Thyroglossal cyst usually presents as a midline neck lump (in the region of the hyoid bone) that is usually painless, smooth and cystic, though if infected, pain can occur. There may be difficulty breathing, dysphagia (difficulty swallowing), or dyspepsia (discomfort in the upper abdomen), especially if the cyst becomes large.

The most common location for a thyroglossal cyst is midline or slightly off midline, between the isthmus of the thyroid and the hyoid bone or just above the hyoid bone. A thyroglossal cyst can develop anywhere along a thyroglossal duct, though cysts within the tongue or in the floor of the mouth are rare.A thyroglossal cyst will move upwards with protrusion of the tongue.Thyroglossal cysts are associated with an increased incidence of ectopic thyroid tissue. Occasionally, a lingual thyroid can be seen as a flattened strawberry-like lump at the base of the tongue.

An infected thyroglossal duct cyst can occur when it is left untreated for a certain amount of time or simply when a thyroglossal duct cyst hasn't been suspected. The degree of infection can be examined as major rim enhancement has occurred, located inferior to the hyoid bone. Soft tissue swelling occurs, along with airway obstruction and trouble swallowing, due to the rapid enlargement of the cyst.

With infections, there can be rare cases where an expression of fluid is projected into the pharynx causing other problems within the neck.