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Exostosis - of Foot, Mouth, Ear, Definition, Pictures

What is Exostosis?

Exostosis is an abnormal projection of bone that resulted from a benign outgrowth of a bone. It is the most common type of bone tumor that is not cancerous and usually occurs on the plate of the bones found at the end of the bones. Exostosis on the other hand can grow on any bone of the body and may cause pain and affect the architectural structure of the bone.

An exostosis is a disorder of the bone characterized by an outgrowth of a bone tissue. The bump caused by the projection of the bone outgrowth may be rounded, sharp or pedunculated and the outgrowth may also vary in size. A lot of problems may be caused by the development of the exostosis. Although exostosis may be asymptomatic, some may suffer from significant pain while exostosis may also stiffness that can impede the range of motion thereby affecting the quality of life.

Environmental stress is the most implicated in exostosis such as in the case of the surfer’s ear. Divers, surfers and other water sports are potential for bony growth within the ear canal as a response to frequent exposure of the ears in cold and flooding water during the water activities. The bony growth in the ear canal thereby impairs the ability to hear as the normal process of sound transmission is being blocked with exostosis. Pain in the ear and the surrounding area of the ear may also be experienced which may tend to be severe depending on the extent of the exostosis.

Exostosis may also occur as a result of damage in the joint. Small bone deposits in the joint or near the joint usually develop due to the strain on the joint that has been damaged. The growth may interfere with the normal movement of the joint therefore impeding the ability of an individual to move such as walking or in bending.

Surgical removal of exostosis is the primary treatment although not all bony outgrowths are recommended for removal. The removal of exostosis depends on the location, size and extent of the outgrowth and if it can severely interfere and affect the quality of life. The onset of exostosis usually occurs during childhood and continuously grows as the child is growing. Exostosis usually stops growing when the child has fully grown. By this time, if the exostosis continues to grow a medical consultation is necessary.

Exostosis of Foot Pictures


Exostosis of Foot

Exostosis can occur in any bone in the body such as in the hands, ears, toes and others. The foot is one of the common areas for exostosis where the outgrowth can be located on top, side and under the foot. Exostosis of the foot can cause considerable pain and impedes daily activities while there are exostosis on the foot that generally causes no pain although may bring a displeasing effect on the architectural structure of the foot.

Exostosis of the foot can occur in any areas of the foot and such are termed appropriately according to the area of the foot that is affected. However, exostosis of the foot generally speaks of the dorsal area of the foot. The bony outgrowth on the dorsum of the foot commonly occurs in any three spots of the dorsal foot and these are:

  • The metatarsal joint area of the foot particularly where the big toe is connected is one area of the foot where the bony outgrowth can develop. Exostosis on this area can lead to the limited movement of the big toe referred as Hallux limitus or it can also lead to Hallux rigidus or the inability of the joint to move.
  • The forefoot that contains the five phalanges or toes is also an area for exostosis of the foot. The bony outgrowth can lead to Haglund’s deformity and can also affect the ability of the toes to bend.
  • The third area of the dorsal foot where exostosis is possible is the midfoot or the area where the 1st metatarsal shaft connects with the cuneiform. The midfoot also forms the arch of the foot and exostosis in this area is termed as Metatarsal cuneiform exostosis.

Exostosis of the dorsal foot can be the result of overpronation, high arches and tight calf muscles. The bony outgrowth can cause undue discomfort and sometimes pain from pressure and friction on the toes. The goal of treatment is to reduce the pressure and friction and to correct the movement of the feet.

Exostosis of Mouth Pictures


Exostosis of Mouth

The mouth or the oral cavity is also an area for the exostosis to develop. The bony protrusion is also known as tori and can be found in any areas of the mouth. The bony overgrowth can be seen in the mandible, facing the cheeks, tongue and lips and can also be seen on the palate or the roof of the mouth. The growth of exostosis in the mouth grows continuously and at a slower rate that it can sometimes go unnoticed.

Exostosis in any area of the mouth can affect its normal function in speech and in food intake although this depends on the extent of the exostosis. It is generally a benign condition but certainly needs monitoring even if the exostosis is not interfering with speech and eating.

Exostosis in the mouth has no definite cause but is thought to be an outcome of mild chronic periosteal ischemia secondary to mild nasal septum pressure. Bruxism or tooth grinding is also considered to be the cause of tori or exostosis.

Tori or exostosis in the mouth is considered a developmental anomaly despite the fact that tori usually occur during adult life and continues to grow throughout life. Tori also has three different appearances such as flat tori, spindle tori which has ridges in the midline, nodular tori that has multiple bony growths with their own base and lobular tori which also has multiple bony growths but with a common base. It comes in various sizes and shapes and tori can be located in any position in the mouth where they are termed appropriately according to the area of existence such as:

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Buccal exostosis is a bony overgrowth located on the outer side of the maxilla that is facing the cheek superior to the teeth. The bony overgrowth can also be seen on the cheek-facing side of the mandible. Buccal exostosis is generally painless and benign without any potential for malignancy although it can cause periodontal disease if the exostosis has enlarged. It seldom develops in the lower jaw and tori can be surgically removed.

Torus palatinus is located in the midline of the hard palate. The bony protrusion is usually rounded and symmetrical with a diameter of less than 2 cm although the size can change throughout life as it continually and slowly grows. Torus palatinus occur during the late teen and early adult years while it is more common in female than in male.

Torus mandibularis is characterized by a bony overgrowth in the mandible particularly on the surface adjacent to the tongue. Most cases of torus mandibularis are bilateral forming a hard and rounded swelling usually on both sides. It is prevalent in Asian countries and more common in male than in female. The size of the bony overgrowth usually changes throughout life and can grow large enough to make the bilateral swellings touch each other along the midline of the oral cavity.

The exostosis in the mouth can be left untreated and need not removed unless it has become large enough that it impedes the normal function or the mouth or interferes with the placement of dentures. A frequent surface ulceration in the mouth and onset of periodontal disease will require removal of tori.

Exostosis of Ear Pictures


Exostosis of Ear

Exostosis in the ear is also referred to as Surfer’s ear and is characterized by bony protrusion within the ear canal. The bony overgrowth within the lining of the ear canal can cause a blockage either partial or complete. It will also cause the ear canal to constrict which trap water and other debris in the ear can subsequently result to ear infection which can cause considerable pain and impair the hearing ability.

Surfer’s ear is so termed because of its common etiology which is the constant exposure of the ear canal from flooding cold water and air. It is not however limited to surfers only but it is also potential for those engaged in water sports and those who frequent the water. The growth of exostosis in the ear canal is usually slowly over the years and may have multiple growths which can constrict the ear canal completely.

Surfer’s ear is common in people between the ages of 30 and 40 years although it can affect at any age tantamount to the time spent in the water without sufficient protection especially during the cold and windy weather. The onset of exostosis in the ear manifests with symptoms of impaired hearing ability which can be temporary or enduring, frequent ear infection causing significant ear pain and a plugging sensation as a result of difficulty in removing debris from the ear.

Surfer’s ear is treated with surgical removal of the bony overgrowth within the ear canal. The surgical procedure requires a patient under general anesthesia and removes the exostosis with the use of a drill. The patient is also required to stay in the hospital for a day or two following the surgical procedure and is advised to keep out of the water for at least eight weeks during the period of recovery.

Subungual Exostosis

Subungual exostosis is a benign bony overgrowth that develops beneath the nail bed usually on the tip of the toe or finger. The lesion in subungual exostosis is a reactive cartilage metaplasia that can be involved in the obliteration of the nail bed. The nail bed of the big is the common area where subungual exostosis occurs and seldom occurs on the finger but usually affect the index and middle finger if an exostosis develops in the finger. The incidence is common among children and young adults and is also more common in female than in male.

The onset of subungual exostosis often exhibits swelling in the surrounding area of the affected site. Onycholysis or the separation of the nail plate from the nail bed occurs as the lump slowly growing upwards and this separation causes pain which may be severe especially when put on with a pressure. Ulceration of the overlying nail may also occur which can also add pain.

The exact cause of subungual exostosis remains unknown and is being linked with factors contributing to the development. Constant irritation of the bone is among the contributing factor believed to cause subungual exostosis. Prolonged infection and a previous trauma to the bone are also considered to cause the bony overgrowth underneath the nail bed.

Surgical excision is the primary choice for method of treatment while resection of exostosis and curettage are found to be effective in treating and curing subungual exostosis. It is a benign condition although it can cause significant pain and discomfort which can affect the quality of life.

Retrocalcaneal Exostosis

Retrocalcaneal exostosis involves the back of the heel where the Achilles tendon is attached to the bone.

Retrocalcaneal exostosis is caused by tightness of the muscles of the calf and the Achilles tendon. This condition often affects adults and is prevalent among women in relation to the type of shoes that women constantly wear which can cause tightness in the muscles of the calf and Achilles tendon. Retrocalcaneal exostosis is also frequently seen in athletes such as those engaged in distance running, basketball, tennis and other sports that involves the use of calf muscles and Achilles tendon.

Pain is the prominent symptom of retrocalcaneal exostosis which is usually perceived at the insertion site of the Achilles tendon. Swelling and tenderness on the posterior aspect of the heel is also common along with the pain. Physical activity and wearing of tight shoes such as high heels can aggravate the pain which can make it more intense.

The treatment for retrocalcaneal exostosis depends on the severity of pain. Nonsteroidal anti-inflammatory drugs are usually prescribed to reduce the inflammation of the tendon and the surrounding tissues including the insertion of the Achilles tendon. Pain skin patch and other pain gels and creams are also recommended to be applied to the affected site to relieve the pain. Decreasing the tension in the Achilles tendon is also another method of managing retrocalcaneal exostosis and is done by utilizing a heel lift which will raise the heel by an inch or more.

Surgery is especially indicated for patients who remain unresponsive to conservative method of managing and relieving pain. The surgical method requires debulking of the Achilles tendon or removal of the exostosis on the back of the heel.

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