Cerebellopontine epidermoid cysts: is the pursuit of complete resection justifiable despite high recurrence rates?

OBJECTIVE Complete removal of an epidermoid cyst (EC) is considered to prevent recurrence. In the cerebellopontine angle (CPA), ECs form adhesions to the surrounding neural and vascular structures, which makes complete removal challenging. At times, this achievement comes with neurological sequelae but can be justified by the promise of long-term disease control. The aim of this study was to investigate when recurrence occurs and whether the extent of resection affects recurrence over long-term follow-up. METHODS This retrospective cohort study included 30 consecutive patients (20 male, mean age 36 years) who underwent surgery for CPA EC from 1975 to 2022 at a single neurosurgical center with a catchment population of 2.2 million. Clinical and imaging data were collected from patient medical records. The extent of tumor resection was evaluated using MRI and compared with surgical reports. Kaplan-Meier survival analysis was performed to estimate reoperation-free survival. RESULTS Eleven patients (37%) required reoperation due to recurrence, 8 (27%) more than once. A total of 24 reoperations were performed. The estimated median reoperation-free survival was 20 years (95% CI 4–36) from the primary surgery and 11 years (95% CI 8–14) from reoperation. The incidence of recurrence followed a linear trend; the longer the follow-up, the higher the chance of recurrence. Neither the postoperative imaging–based or surgeon-assessed extent of tumor removal predicted recurrence. New postoperative symptoms were observed in 50% of patients. Although many of the new symptoms resolved during the first 3 months, only 16% (3/19) of patients with follow-up > 1 year remained asymptomatic at the end of follow-up. CONCLUSIONS During long-term follow-up, recurrence of CPA EC was frequent and occured with all grades of resection. Given the relatively high risk of neurological sequelae associated with surgery, the surgical strategy should prioritize safe resection over aggressive attempts at total removal. Even in cases of complete resection, routine imaging follow-up at intervals of 5 to 10 years, with the possibility of extending surveillance up to 20 years, is recommended.