Choristoma: Definition, Risk Factors, Causes, Symptoms, Diagnosis and Treatment

It is a well-circumscribed benign growth of normal, mature bone tissue at ectopic sites.

Choristoma of the bone is normal bone tissue in an ectopic position. In the oral region, the lingual localization occurs more frequently and the mass is usually located on the dorsum of the tongue.

The definitive diagnosis is obtained only after histopathological examination. The etiology remains debatable.

The term choristoma is used to describe the growth of normal tissue in an abnormal position. Choristoma of the mouth can be made up of several different types of tissues.

These include bone, cartilage, gastric mucosa, glial tissue, and sebaceous gland tumor masses.

Choristoma of the tongue is an extremely rare condition, of which only 66 cases have been reported in the literature so far. The bone histotype is the most described among the choristomas.

In the oral region, the lingual localization occurs more frequently and the mass is usually located on the dorsum of the tongue.

  • The dermoid cyst is made up of the components of the epidermis and dermis, including hair.
  • Choristoma of the oral cavity may contain epidermal (skin, hair follicles, sebaceous glands), bone, cartilage, lingual thyroid, gastric, respiratory, salivary or glial components.
  • Fakomatous choristoma of the eyelid or orbit with embryological lens precursor cells (lenticular eel).
  • Epibulbar or corneal choristoma arise in the limbus of the eye and can include dermoid, lipodermoid, or other tissues.
  • The choristoma within the ear canal usually contains cartilage.
  • A salivary gland choristoma has been reported in the anterior chest wall and in the breast.

Dermoids are firm, dome-shaped, white-yellow papules, typically in or on the limbus, most commonly in the inferotemporal quadrant, they may also involve the central cornea. The size varies from a few millimeters to more than 1 cm.

Dermoids can occur in isolation or, particularly when they are bilateral, as a manifestation of a congenital complex such as Goldenhar syndrome (oculoauriculovertebral dysgenesis, characterized by epibulbar dermoid, upper eyelid coloboma, preauricular skin tags, and vertebral abnormalities).

They can also occur as a manifestation of linear sebaceous nevus syndrome ( oculoneurocutaneous disorder ). A dermoid often contains dermal adnexal structures. The superficial epithelium may or may not be keratinized.

Lipodermoids (or dermolipomas) occur most frequently in the superotemporal quadrant toward the fornix and may extend posteriorly into the orbit.

As a result of its adipose tissue component, a lipodermoid is softer and more yellowish than a dermoid. Dermal attachment structures may or may not be present. Lipodermoids, like dermoids, can be associated with Goldenhar syndrome or linear sebaceous nevus syndrome.

Who can get choristomas?

Choristoma can be diagnosed at any age from birth to old age. All epidermal choristomas have occurred in males.

Most cases of lingual bone choristoma have been reported in women in their third and fourth decades. Chamomatous choristoma and salivary gland choristoma tend to appear in newborns.

What Causes Choristoma?

Choristoma is a developmental abnormality. For example, a dermoid cyst arises from trapped epithelium along lines of embryonic fusion. The reason why they present late in life in some cases is unknown. One theory is that it may be due to chronic irritation.

What are the symptoms of choristoma?

Epidermal choristoma on the back of the tongue most often presents as a brown to black pigmented macula of variable size (3-11 mm). The differential diagnosis of pigmented macular choristoma on the tongue includes congenital melanotic macula and melanocytic nevi.

The bone choristoma presents as a hard pedunculated lump, painless on the back of the tongue, posterior to the foramen cecum. Oral choristoma can also occur on the gum or oral mucosa.

Choristoma phakomatous has a similar appearance, but arises around the orbit or region of the eyelid. The clinical concern may be rhabdomyosarcoma.

A choristoma in the ear canal presents as a mass that causes hearing loss and can predispose to infection.

How is choristoma diagnosed?

Choristoma is diagnosed by biopsy or excision, finding histologic features that confirm that the cells are microscopically normal in an abnormal location.

What is the treatment of choristoma?

Choristoma is usually removed because the most common treatment of choice is surgical excision.

The lesions are benign with little risk of malignant transformation. Recurrence rates after excision are extremely low.