The endolymphatic sac tumor: challenges in the eradication of a localized disease.

OBJECTIVE: Identify the critical points that lead to recurrences and lack of radicality in endolymphatic sac tumors (ELSTs). STUDY
DESIGN: Retrospective case study and review of the literature.
SETTING: Tertiary referral center. PATIENTS: Thirteen cases of ELST were included in the study and their preoperative, intraoperative and postoperative data were analyzed and compared to a review of the literature. INTERVENTION(S): Therapeutical. MAIN OUTCOME MEASURE(S): Prevalence of recurrent and residual tumors, comparison to the literature and analysis of ELST characteristics.
RESULTS: Diagnosis was made 26 ± 17 months after the onset of symptomatology, and an ELST was preoperatively suspected in only six cases. At the time of surgery, 10 patients suffered from hearing loss. Preoperative symptoms or audiometry could not predict labyrinth infiltration, although speech discrimination scores were significantly associated with labyrinth infiltration (p = 0.0413). The labyrinth was infiltrated in 8 cases (57.1%), and in 7 cases (46.7%) the tumor eroded the carotid canal, whereas 6 cases (40%) presented an intradural extension. A gross total resection was achieved in 11 cases. There were two residual tumors, one of which because of profuse bleeding, and one recurrence (23.1%). A mean of 22.8% of recurrent or residual tumors are described in the literature based on 242 published cases, in more than half of the cases as a consequence of subtotal tumor resection (STR).
CONCLUSIONS: Recurrence derives mostly from the difficulty to identify the extension of the tumor due to the extensive bone infiltration. Accurate diagnosis and correct preoperative planning, with embolization when possible, will facilitate surgery and avoid STR due to intraoperative bleeding. Long follow-ups are important in order to avoid insidious recurrences.