Objective: To report the first large case series of extremely rare bilateral congenital cholesteatoma (CC).
Study design: A retrospective cohort study.
Setting: University hospital otology referral clinic.
Patients: Six hundred four children with surgically confirmed CC.
Main outcome measures: The bilateral CCs were compared with the unilateral CCs.
Results: The incidence of bilateral CC was 3.6% (22/615) per case or 1.8% (11/604) per child. Bilateral CC did not differ from unilateral CC regarding its demographics, and invasiveness by the proportion of advanced CC as 31.8% (7/22) versus 28.2% (167/594). But the invasiveness or location randomly differed between the ears, that advanced CC per child was higher as 45.4% (5/11). Bilateral exploration was attempted with a concern for hearing loss, which featured a combination of laser myringotomy to treat early CC and endaural laser-assisted single-stage inside-out cholesteatoma surgery to treat advanced CC. Bilateral exploration was difficult in three children with initially negative otoendoscopy. Among the seven advanced CC, proportion of anterior type was 71.4% (5/7), who all exhibited more than 20 dB HL, but two posterior type retained normal hearing. Therefore, bilateral advanced CCs of anterior origin showed poorest hearing outcome as bilateral more than 20 dB HL, which were in two children. Six second-look operations and one third-look operation were required to treat six residual CCs (30%) in four children (40%), including bilateral residual CC in two (20%); such reoperations were significantly more frequent than in unilateral CC.
Conclusion: The diagnosis of bilateral CC required high index of suspicion from TBCT, and early bilateral exploration.