Surgery for Pediatric Cholesteatoma Workup

No laboratory diagnostic tests are generally necessary for cholesteatoma.

• Some surgeons believe that any patient with a cholesteatoma scheduled for surgical intervention should have a preoperative CT scan. These surgeons believe that useful information is obtained in every circumstance and, consequently, that the expense and radiation exposure is always justified. The imaging modality of choice is a fine-cut CT scan without intravenous contrast. CT scans can reveal the following subtle bony changes:

  • Scutal erosion
  • Labyrinthine fistula
  • Defects in the tegmen
  • Details of ossicular involvement
  • Details of ossicular erosion or discontinuity
  • Anomalies, erosion, or invasion of the facial nerve canalAn unenhanced CT scan demonstrating that the posterior canal wall has been eroded and the external auditory canal has filled with cholesteatoma, pus, and debris. Surprisingly, the middle ear appears relatively free of disease, a characteristic of primary acquired cholesteatomas.
• CT scanning cannot always distinguish between granulation tissue and cholesteatoma.

  • Even technically excellent, fine-cut CT scans cannot always reveal the full extent of disease.
  • The surgeon, therefore, cannot always predict what will be encountered intraoperatively.
  • Both the operating surgeon and the patient must understand these limitations of the preoperative assessment and must prepare for intraoperative surprises.
• Other surgeons reserve preoperative imaging for only special cases and are comfortable performing some operations without preoperative imaging. These surgeons are likely to request a preoperative CT scan in the following circumstances:

  • Doubtful diagnosis
    • The diagnosis may be in doubt.
    • CT scanning can distinguish between shallow retractions without soft tissue extension into the epitympanic space and an extensive soft tissue mass with bony erosion.
    • CT scanning may be helpful in individuals who already have had tympanomastoid surgery. In this group of patients, a white mass behind the TM can represent tympanosclerosis, cartilage deliberately placed at a previous operation, or recurrent cholesteatoma. CT scanning frequently helps determine which.
  • A patient who wishes to avoid surgery: Information from a CT scan may help a surgeon advise the patient and parents and/or caregivers that the presence of extensive disease, labyrinthine fistula, encroachment on the fallopian canal, and involvement of the oval window niche increase the risk of nonsurgical management.
  • If ossicular involvement is apparent on preoperative CT scans, then parents can be counseled that ossicular removal may be necessary and that a significant postoperative conductive hearing loss should be expected.
  • Indeterminate underlying anatomy and unclear extent of disease as the result of previous surgery
  • Reasonable expectation of congenital anomalies (eg, atresia, craniofacial anomalies)
  • Suspected complications
• MRI is useful when the following very specific problems involving surrounding soft tissues are expected:

  • Dural involvement, invasion, and/or inflammation
  • Subdural or epidural abscess
  • The presence of herniated brain into the mastoid cavity
  • Inflammation of the membranous labyrinth or facial nerve
  • Intracranial invasion
  • Sigmoid sinus thrombosis
  • Meningitis

• Audiometry

  • In most circumstances, audiometry should be performed prior to surgery and should include air and bone conduction and speech discrimination testing.
  • Infrequently, a serious complication of cholesteatoma requires urgent surgery; in these patients, audiometric testing can be omitted.

The histology of surgically removed cholesteatoma specimens demonstrates typical squamous epithelium. The histology is indistinguishable from sebaceous cysts or keratomas removed from any other portion of the body.