Congenital Cholesteatoma

Nancy M. Young, MD

Congenital cholesteatomas are benign tumors of the temporal bone that usually originate within the middle ear space. They classically appear as a white mass beneath an intact tympanic membrane, and early diagnosis on routine otoscopic examination is often possible. Early diagnosis and treatment can lead to better outcomes and decreased likelihood of recurrence. Cholesteatomas are epidermoid cysts, in other words, "skin in the wrong place." The majority of childhood cholesteatomas are not congenital, but acquired secondary to chronic middle ear disease. Skin from the outer surface of the drum gains access to the middle ear through a retraction pocket or a tympanic membrane perforation. In contrast, congenital cholesteatoma is thought to occur secondary to failure of normal involution of the epidermoid formation, a collection of stratified squamous epidermoid cells that appear during fetal development and are thought to play a role in development of the middle ear mucosa.These squamous skin cells grow slowly and become clinically apparent as a cholesteatoma during childhood.

The typical presentation of congenital cholesteatoma is a white mass beneath the tympanic membrane.The majority of cases involve the anterior superior quadrant of the middle ear, although they can arise from other locations. Early diagnosis of cholesteatomas that originate in the anterior superior quadrant is beneficial because no critical anatomic structures are present in this area (Figure 1). Once the tumor grows to involve the posterior superior quadrant, involvement of the ossicular chain is likely, even in the absence of conductive hearing loss (Figure 2). Tumors in this area are also more likely to have extended above the middle ear space into the attic, where they can continue to grow into the mastoid.

Figure 1. A small congenital cholesteatoma was found at time of a well-child visit. The tumor is seen through an intact tympanic membrane. Only the anterosuperior quadrant of the middle ear space appears involved. At surgery, the tumor was encapsulated and did not involve the ossicles or extend beyond the middle ear.

Figure 2. A large congenital cholesteatoma, found subsequent to hearing loss identified at time of a school hearing screening test. The tumor completely fills all visible middle ear space beneath the tympanic membrane. At surgery, ossicular erosion was present as well as tumor extension into the attic and mastoid.

DIFFERENTIAL DIAGNOSIS

Congenital cholesteatomas are confused most often with myringosclerosis, thickening and calcification of the tympanic membrane secondary to inflammation. The presence of cholesteatoma in the middle ear versus myringosclerosis can often be distinguished by pneumatic otoscopy. The myringosclerotic plaque will move with the drum; whereas, with negative pressure, the normal drum is pulled away from the cholesteatoma.However, pneumatic otoscopy may not be helpful if the overlying drum is thickened or the middle ear space is not well ventilated. Rarely, epidermoid cysts can develop within the tympanic membrane itself. The origin of this type of epidermoid cyst is unknown. Another uncommon entity that can be confused with congenital cholesteatoma is osteoma of the middle ear.

PRESENTATION

Asymptomatic congenital cholesteatomas occupying the anterior superior aspect of the middle ear may be found on routine otoscopic examination at the time of a well-child evaluation. These lesions are difficult to diagnose in children who also have a history of recurrent infection or chronic effusion, due to thickening of the drum or the presence of fluid. Therefore, the initial diagnosis might be made in the operating room while tubes are being placed to manage otitis media. Another common presentation is hearing loss found at the time of a school hearing screening test. Diagnostic behavioral hearing testing confirms the presence of conductive hearing loss. These children will have significant involvement of part of the ossicular chain. Otoscopic examination may reveal a middle ear mass. However, a minority of children who have hearing loss secondary to congenital cholesteatoma have involvement of the stapes or incus which cannot be seen on otoscopic exam. A high resolution, thin-section CT scan typically demonstrates soft tissue surrounding the ossicles, which may be confused with residual mucosal disease secondary to otitis media.

An enlarging cholesteatoma will cause tympanic membrane perforation and chronic or intermittent otorrhea. When diagnosis is delayed to this point, congenital cholesteatoma cannot be distinguished with certainty from one that is acquired.

MANAGEMENT

Treatment for cholesteatoma is prompt surgical excision. No preoperative imaging is necessary if the borders of a small growth can be visualized. However, if the superior extent of the mass is uncertain, high-resolution CT scanning of the temporal bone can help determine the presence and degree of extension into the attic and mastoid. Knowledge of the extent of disease is useful for surgical planning and preoperative counseling. Children with extensive disease may require a second-stage procedure to look for regrowth of microscopic residual disease and to reconstruct the ossicular chain. This second procedure usually is done 6 to 12 months after the initial surgery. Recurrence of the tumor over time is a concern in all patients diagnosed with cholesteatoma. Therefore, long-term follow-up is critical in order to monitor for recurrent disease.

CONCLUSION

Congenital cholesteatomas are benign but locally destructive tumors of the ear. They usually are asymptomatic in the early stages of growth and, therefore, may be extensive by the time of initial diagnosis. Early diagnosis of congenital cholesteatoma is advantageous and may be achieved during careful in-office otoscopic examination. Office diagnosis may not be possible in children with concomitant middle ear disease that can obscure the classic presentation of a white mass beneath tympanic membrane.

REFERENCES

1. Levenson MJ, Michaels L, Parisier SC, Juarbe C. Congenital cholesteatomas in children: an embryologic correlation. Laryngoscope 1988;98: 949–955.

2. Parisier SC, Levenson MJ, Edelstein DR, Bindra GS, Han JC, Dolitsky JN. Management of congenital pediatric cholesteatomas. Am J Otol 1989;10: 121–123.

3. McGill TJ, Merchant S, Healy GB, Friedman EM. Congenital cholesteatoma of the middle ear in children: a clinical and histopathological report. Laryngoscope 1991;101: 606–613.

4. Friedberg J. Congenital cholesteatoma. Laryngoscope 1994;104: 1–2.

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