Chapter 82

Cholesteatoma

Terry Mahan Buttaro

Definition

A cholesteatoma (sometimes referred to as a keratoma) is an abnormal accumulation of squamous epithelial cells typically found within the middle ear, mastoid air spaces, or epitympanum.¹ Cholesteatomas can be acquired or congenital, but most often are acquired.

Pathophysiology

The pathogenesis of congenital cholesteatoma is the presence of embryonic squamous epithelial cells in an ear without a history of tympanic membrane (TM) perforation or ear infection.¹ Congenital cholesteatomas arise in fetal development, but the exact cause is unclear. Primary acquired cholesteatomas are also the result of an unknown pathology but are related to retraction of the TM, usually in the pars flaccida.¹ The cause may be related to abnormal function of the eustachian tube or a chronic inflammatory cascade of events initiated by a middle ear infection.² The result is an accumulation of squamous epithelium, progressive erosion of the associated structures, and destruction of the delicate bones of the ossicular chain. Secondary acquired cholesteatomas develop as squamous epithelial cells enter the middle ear either after a surgical procedure (e.g., tympanoplasty) or as a direct consequence of epithelial cell shifting from the TM.¹ Advanced cholesteatomas can become secondarily infected. Typical organisms causing infected cholesteatomas include Pseudomonas aeruginosa, Proteus species, Enterobacter, Staphylococcus, Streptococcus, and anaerobes.¹ Over time, cholesteatomas can spread into intratemporal structures, causing tinnitus, otorrhea, hearing loss, twitching of the facial nerve, or paralysis of the facial nerve from infection or compression. Even with treatment, recurrence is possible.³

Clinical Presentation

Congenital cholesteatomas may slowly enlarge for years and be asymptomatic. Otorrhea or hearing loss is often the presenting complaint. Acquired lesions are associated with recurrent or persistent purulent ear infections and tinnitus. Impaired hearing may be the first sign of middle ear destruction from a cholesteatoma.⁴ Rarely the inflammatory process in the middle ear can result in vertigo, or the dizziness can occur from erosion of the labyrinth by the cholesteatoma.

Physical Examination

For a thorough otoscopic examination to be performed, several things should be taken into consideration. The light source on the otoscope must have adequate brightness to provide sufficient illumination of the inner ear. The entire TM should be inspected, particularly the posterosuperior quadrant and the anterosuperior quadrant, which are the most common locations of acquired and congenital cholesteatomas, respectively. Removal of cerumen or debris from infection may be necessary for adequate exposure of the entire TM.⁴ On otoscopic examination, congenital cholesteatomas are typically identified as a pale whitish discoloration or spherical white cyst behind an intact TM. In primary acquired cholesteatoma, findings include retraction of the pars flaccida and, although less commonly, the pars tensa. Retraction pockets are identified by careful inspection of the TM and can be shallow or deep. Shallow pockets may be seen with otoscopy; deep pockets can contain debris and not be visible. Other common findings include a whitish keratin mass, purulent otorrhea, polyps, granulation tissue on the surface of the TM, and ossicular erosion. In secondary acquired cholesteatoma, the findings depend on the cause. The physical examination should include the entire ear, and the function of the facial nerve (cranial nerve VII) should be evaluated. Routine examination techniques for nystagmus and balance function may be warranted for patients with vestibular dysfunction.

Only gold members can continue reading. Log In or Register to continue