Preauricular sinuses and cysts result from developmental defects of the first and second pharyngeal arches. This and other congenital ear malformations are sometimes associated with renal anomalies. They may be present in Beckwith–Wiedemann syndrome, and in rare cases, they may be associated with branchio-oto-renal syndrome.

Occasionally a preauricular sinus or cyst can become infected.

Most preauricular sinuses are asymptomatic, and remain untreated unless they become infected too often. Preauricular sinuses can be excised with surgery which, because of their close proximity to the facial nerve, is performed by an appropriately trained, experienced surgeon (e.g. a specialist General Surgeon, a Plastic Surgeon, an otolaryngologist (Ear, Nose, Throat surgeon) or an Oral and Maxillofacial Surgeon).

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 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.

A cutaneous sinus of dental origin is where a dental infection drains onto the surface of the skin of the face or neck. This is uncommon as usually dental infections drain into the mouth, typically forming a parulis ("gumboil").

Cutaneous sinuses of dental origin tend to occur under the chin or mandible. Without elimination of the source of the infection, the lesion tends to have a relapsing and remitting course, with healing periods and periods of purulent discharge.

Cutaneous sinus tracts may result in fibrosis and scarring whcich may cause cosmetic concern. Sometimes minor surgery is carried out to remove the residual lesion.

Symptoms of polyps include nasal congestion, sinusitis, loss of smell, thick nasal discharge, facial pressure, nasal speech, and mouth breathing. Recurrent sinusitis can result from polyps. Long-term, nasal polyps can cause destruction of the nasal bones and widening of the nose.

As polyps grow larger, they eventually prolapse into the nasal cavity resulting in symptoms. The most prominent symptoms of nasal polyps result blockage of the nasal passage.

People with nasal polyps due to aspirin intolerance often have symptoms known as Samter's triad, which consists of asthma worse with aspirin, a skin rash caused by aspirin, and chronic nasal polyps.

Pilonidal cysts are itchy and are often very painful, and typically occur between the ages of 15 and 35. Although usually found near the coccyx, the condition can also affect the navel, armpit or genital region, though these locations are much rarer.

Symptoms include:

- Pain/discomfort or swelling above the anus or near the tailbone that comes and goes

- Opaque yellow (purulent) or bloody discharge from the tailbone area

- Unexpected moisture in the tailbone region

- Discomfort with sitting on the tailbone, doing sit-ups or riding a bike (any activities that roll over the tailbone area)

Some people with a pilonidal cyst will be asymptomatic.

A concha bullosa is a pneumatized (air-filled) cavity within a turbinate in the nose. (Concha is another term for turbinate.) Bullosa refers to the air-filled cavity within the turbinate. It is a normal anatomic variant seen in up to half the population. Occasionally, a large concha bullosa within a turbinate may cause it to bulge sufficiently to obstruct the opening of an adjacent sinus, possibly leading to recurrent sinusitis. In such a case the turbinate can be reduced in size by endoscopic nasal surgery (turbinectomy). The presence of a concha bullosa is often associated with deviation of the nasal septum toward the opposite side of the nasal cavity. Although it is thought that sinusitis or sinus pathology has relation to concha bullosa, no strong statistical correlation has been demonstrated.

Most branchial cleft cysts present as a smooth, slowly enlarging lateral neck mass that may increase in size after an upper respiratory tract infection. The fistulas, when present, are asymptomatic, but may become infected.

Oroantral fistula (OAF) is an abnormal condition of the face where the maxillary sinus is exposed to the oral cavity through an epithelialised fistula. This term signifies pathology and it is not to be confused with oroantral communication (OAC). OAC if left untreated can either heal spontaneously or progress into OAF. The fistulous opening may be situated on the alveolus.

Clinical examination and x rays can help diagnose the condition. For examples :

- Valsalva test (nose blowing test): Ask the patient to pinch the nostrils together and open the mouth, then blow gently through the nose. Observe if there is passage of air or bubbling of blood in the post extraction alveolus as the trapped air from closed nostrils is forced into the mouth through any oroantral communication. Gentle suction applied to the socket often produces a characteristic hollow sound.

- Perform a complete extra- and intra-oral examination using a dental mirror under good lighting, look for granulation tissue in the socket and openings into the antrum.

- Panoramic radiograph or paranasal computed tomography can help to locate the fistula, the size of it and to determine the presence of sinusitis and other foreign bodies. Other methods like radiographs (occipitomental, OPG and periapical views) can also be used to confirm the presence of any oroantral fistulas.

- To test the patency of communication the patient is asked to rinse the mouth or water is flushed in the tooth socket.

- Unilateral epistaxis is seen in case of collection of blood in the sinus cavity.

- Do not probe or irrigate the site, because it may lead to sinusitis or push foreign bodies, such as contaminated fragments, or oral flora further into the antrum. Hence, leading to the formation of a new fistula or widen an existing one.

A sinus tract, or small channel, may originate from the source of infection and open to the surface of the skin. Material from the cyst may drain through the pilonidal sinus. A pilonidal cyst is usually painful, but with draining, the patient might not feel pain.

Intraoral dental sinus (also termed a parulis and commonly, a gumboil) is an oral lesion characterized by a soft erythematous papule (red spot) that develops on the alveolar process in association with a non-vital tooth and accompanying dental abscess. A parulis is made up of inflamed granulation tissue.

Less commonly, dental infections drain onto the surface of the skin, forming a cutaneous sinus of dental origin.

This condition is often resolved by endodontic treatment and does not have indication for antibiotic use. This is a common mistake among health professionals.

They are divided into three types based on their location:

- commissural pits, which are small pits near the labial commissure of the mouth,

- a pit in the upper lip, in which case it may be called a midline sinus of the upper lip, and

- pits in the lower lip, in which case it may be called a congenital sinus of the lower lip.

In some cases commissural pits have been reported in combination with preauricaluar pits, which are near the ear.

Nasal polyps (NP) are noncancerous growths within the nose or sinuses. Symptoms include trouble breathing through the nose, loss of smell, decreased taste, post nasal drip, and a runny nose. The growths are sac-like, movable, and nontender, though face pain may occasionally occur. They typically occur in both nostrils in those who are affected. Complications may include sinusitis and broadening of the nose.

The exact cause is unclear. They may be related to chronic inflammation of the lining of the sinuses. They occur more commonly among people who have allergies, cystic fibrosis, aspirin sensitivity, or certain infections. The polyp itself represents an overgrowth of the mucous membranes. Diagnosis may occur by looking up the nose. A CT scan may be used to determine the number of polyps and help plan surgery.

Treatment is typically with steroids, often in the form of a nasal spray. If this is not effective surgery may be considered. The condition often recurs following surgery, thus continued use of a steroid nasal sprays is often recommended. Antihistamines may help with symptoms but do not change the underlying disease. Antibiotics are not required for treatment unless an infection occurs.

About 4% of people currently have nasal polyps while up to 40% of people develop them at some point in their life. They most often occur after the age of 20 and are more frequent in males than females. Nasal polyps have been described since at least the time of the Ancient Egyptians.

Pneumosinus dilatans is a condition consisting of abnormal expansion or dilatation of one or more paranasal sinuses. It most often affects the frontal sinus, and can cause damage to vision due to pressure on the nearby optic nerve. The preferred treatment is endoscopic surgery to deflate the sinus.

A branchial cleft cyst is a cyst in the skin of the lateral part of the neck. It can but does not necessarily have an opening to the skin surface called a fistula. The cause is usually a developmental abnormality arising in the early prenatal period, typically failure of obliteration of the second branchial cleft, i.e. failure of fusion of the second and third branchial arches. Less commonly, the cysts can develop from the first, third, or fourth clefts, and their location and the location of associated fistulas differs accordingly.

Adenomyomatosis is a benign condition characterized by hyperplastic changes of unknown cause involving the wall of the gallbladder.

Adenomyomatosis is caused by an overgrowth of the mucosa, thickening of the muscular wall, and formation of intramural diverticula or sinus tracts termed Rokitansky-Aschoff sinuses.

Ethmoid hematoma is a progressive and locally destructive disease of horses. It is indicated by a mass in the paranasal sinuses that resembles a tumor, but is not neoplastic by any means. The origins and causes of the ethmoid hematoma are generally unknown. Large hematomas usually start within the ethmoid labyrinth, and smaller ones tend to begin on the sinus floor.

The hematoma usually extends into the nasal passage. A growing hematoma causes pressure necrosis of the bone surrounding the hematoma, but only on rare occasions does it cause facial distortion. It is most commonly seen in horses older than six years. Mild, persistent, spontaneous, intermittent, and unilateral epistaxis is the most common sign clinically.

Pott's puffy tumor, first described by Sir Percivall Pott in 1760, is a rare clinical entity characterized by subperiosteal abscess associated with osteomyelitis. It is characterized by an osteomyelitis of the frontal bone, either direct or through haematogenic spread. This results in a swelling on the forehead, hence the name. The infection can also spread inwards, leading to an intracranial abscess. Pott's puffy tumor can be associated with cortical vein thrombosis, epidural abscess, subdural empyema, and brain abscess. The cause of vein thrombosis is explained by venous drainage of the frontal sinus, which occurs through diploic veins, which communicate with the dural venous plexus; septic thrombi can potentially evolve from foci within the frontal sinus and propagate through this venous system. This type of chronic osteomyelitis of the frontal bone is confused with acute sub-periosteal abscess of the frontal bone, which presents as a discrete collection over the frontal sinus.

Although it can affect all ages, it is mostly found among teenagers and adolescents. It is usually seen as a complication of frontal sinusitis or trauma. Medical imaging can be of use in the diagnosis and evaluation of the underlying cause and extent of the condition. Ultrasound is able to identify frontal bone osteomyelitis, while computed tomography (CT) can evaluate bony erosion, and along with magnetic resonance imaging (MRI), can better appreciate the underlying cause and extent of possible intra-cranial extension/involvement.

An odontogenic infection is an infection that originates within a tooth or in the closely surrounding tissues. The term is derived from "" (from ancient Greek "odous" - "tooth") and "" (from Greek "genos" - "birth"). Odontogenic infections may remain localized to the region where they started, or spread into adjacent or distant areas.

It is estimated that 90-95% of all orofacial infections originate from the teeth or their supporting structures. Furthermore, about 70% of odontogenic infections occur as periapical inflammation, i.e. acute periapical periodontitis or a periapical abscess. The next most common form of odontogenic infection is the periodontal abscess.

A congenital lip pit or lip sinus is a congenital disorder characterized by the presence of pits and possibly associated fistulas in the lips. They are often hereditary, and may occur alone or in association with cleft lip and palate, termed Van der Woude syndrome.

Neoplasm should be considered in any patient presenting with NLD obstruction.In patients with an atypical presentation, including younger age and male gender, further workup is appropriate. Bloody punctal discharge or lacrimal sac distension above the medial canthal tendon is also highly suggestive of neoplasm.

Silent sinus syndrome is a spontaneous, asymptomatic collapse of the maxillary sinus and orbital floor associated with negative sinus pressures. It can cause painless facial asymmetry, diplopia and enophthalmos. Usually the diagnosis is suspected clinically, and it can be confirmed radiologically by characteristic imaging features that include maxillary sinus outlet obstruction, sinus opacification, and sinus volume loss caused by inward retraction of the sinus walls. Treatment is surgical involving making an outlet for mucous drainage from the obstructed sinus.