Холестеатома среднего уха: причины, диагностика и лечение.

Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Cholesteatomas are not cancerous as the name may suggest, but can cause significant problems because of their erosive and expansile properties. This can result in the destruction of the bones of the middle ear (ossicles), as well as growth through the base of the skull into the brain. They often become infected and can result in chronically draining ears. Treatment almost always consists of surgical removal. This can result in nerve deterioration, imbalance, vertigo, and deafness early in the disease. It can also affect and erode, through the enzymes it produces, the thin bone structure that isolates the top of the ear from the brain, as well as lay the covering of the brain open to infection with serious complications (rarely even death due to brain abscess and sepsis). Both the acquired as well as the congenital types of the disease can affect the facial nerve that extends from the brain to the face and passes through the inner and middle ear and leaves at the anterior tip of the mastoid bone, and then rises to the front of the ear and extends into the upper and lower face.

More commonly, keratin accumulates in a pouch of tympanic membrane which extends into the middle ear space. This abnormal folding or 'retraction' of the tympanic membrane arises in one of the following ways:
Jackler's theory: Mucosal coupling with traction generated by interaction of migrating opposing surfaces leading to formation of cholesteatoma. Wittmaack's theory: Invagination of tympanic membrane from the attic or part of pars tensa in the form of retraction pockets lead to the formation of cholesteatoma. Ruedi's theory: The basal cells of germinal layer of skin proliferate under the influence of infection and lay down keratinising squamous epithelium. Habermann's theory: The epithelium from the meatus or outer drum surface grows into the middle ear through a pre existing perforation and form cholesteatoma. Cholesteatoma may also arise as a result of metaplasia of the middle ear mucosa or implantation following trauma.

Cholesteatoma is diagnosed by a medical doctor by physical examination of the ear. A CT scan may help to rule out other, often more serious causes for the patient's clinical presentation. Non ionizing radiation imaging techniques (MRI) may be suitable to replace a CT scan, if determined necessary by a physician.

Cholesteatoma is a persistent disease. Once the diagnosis of cholesteatoma is made in a patient who can tolerate a general anesthetic, the standard treatment is to surgically remove the growth. The challenge of cholesteatoma surgery is to permanently remove the cholesteatoma whilst retaining or reconstructing the normal functions of the structures housed within the temporal bone. The general objective of cholesteatoma surgery has two parts. It is both directed against the underlying pathology and directed towards maintaining the normal functions of the temporal bone. These aims are conflicting and this makes cholesteatoma surgery extremely challenging. Sometimes, the situation results in a clash of surgical aims. The need to fully remove a progressive disease like cholesteatoma is the surgeon's first priority. Preservation of hearing is secondary to this primary aim. If the disease can be removed easily so that there is no increased risk of residual disease, then the ossicles may be preserved. If the disease is difficult to remove, so that there is an increased risk of residual disease, then removal of involved ossicles in order to fully clear cholesteatoma has generally been regarded as necessary and reasonable. In other words, the aims of cholesteatoma treatment form a hierarchy. The paramount objective is the complete removal of cholesteatoma. The remaining objectives, such as hearing preservation, are subordinate to the need for complete removal of cholesteatoma. This hierarchy of aims has led to the development of a wide range of strategies for the treatment of cholesteatoma.

Recent findings indicate that the keratinizing squamous epithelium of the middle ear could be subjected to human papillomavirus infection. Indeed, DNA belonging to oncogenic HPV16 has been detected in cholesteatoma tissues, thereby underlining that keratinizing squamous epithelia could potentially be a target tissue for HPV infection. Cholesteatoma affects all age groups, from infants through to the elderly. The peak incidence occurs in the second decade.