Tumors and pseudotumors of the endolymphatic sac.

This article reports on the presentation, diagnosis, management, and treatment outcomes of lesions of the endolymphatic sac in patients treated at a tertiary neurotology referral center. It summarizes survival results in the largest series groups and presents a new diagnostic entity of pseudotumor of the endolymphatic sac. The study includes retrospective review of all patients diagnosed with lesions of the endolymphatic sac within our practice between 1994 and 2005 as well as review of the literature. The primary outcome measure was survival, and the secondary outcome measure was disease-free survival following definitive resection. Postoperative complications were assessed. Survival characteristics of the largest reported case series groups were reviewed. Five cases of endolymphatic sac lesions were identified. Of these, three were true endolymphatic sac tumors and two were inflammatory pseudotumors of the endolymphatic sac. All three of the endolymphatic sac tumors patients survived (100%), and two of the three had disease-free survival (67%). Two of three patients maintained persistent facial paresis postoperatively. Both patients with benign pseudotumors survived (100%). Our study concluded that endolymphatic sac tumors are rare neoplasms of the temporal bone that, although locally aggressive and invasive, have excellent prognosis for survival with complete resection. We report a new entity of pseudotumor of the endolymphatic sac that mimics true sac tumors in every respect on presentation but which is non-neoplastic in origin.