[Clinical characteristics and surgical outcomes of the endolymphatic sac tumor]

Objective:To summarize the clinical characteristics and surgical outcomes of endolymphatic sac tumor（ELST）, and improve the experience of diagnosis and treatment of this disease. Methods:A retrospective analysis was conducted on the clinical data of patients with ELST who underwent surgical treatment by the Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University from January 2015 to December 2024.The clinical and image features, perioperative management, surgical methods and follow-up results of the disease were summarized. Results:Of the 6 cases, 4 were male and 2 were female. The primary clinical characteristics were hearing loss（6 cases）, tinnitus（5 cases）, dizziness（2 cases）, facial paralysis（1 case）, and headache（1 case）. CT and MRI of temporal bone were performed in all cases. The manifestation of CT was a space occupying lesion centered on the region of endolymphatic sac, accompanied by bone destruction and intertumoral calcification. MRI showed tumor center isosignal and peripheral hypersignal in T1 and T2 sequences in 3 cases, and mixed hypersignal in T1 and T2 sequences in 3 cases. Enhancement was observed in all cases on the enhanced scan. 5 cases underwent DSA examination and showed the tumors were supplied by the occipital artery（2 cases）, posterior auricular artery（4 cases）, and the bunch of internal carotid artery（1 case）. Embolization of the feeding artery was performed in 3 patients. Five patients underwent tumor resection. Translabyrinthine approach were performed in 4 cases, and middle cranial fossa approach was performed in 1 case. All cases followed up for 24 to 70 months with no distant metastases or death. Two patients experienced twice recurrences and were treated with surgical operation. The tumors were found to be closely related to the internal auditory canal or dura during the surgery. Conclusion:The clinical manifestations of ELST are not typical, and hearing loss is the most common clinical symptom. CT and MRI exhibit typical imaging characteristics. ELST has a risk of recurrence, and the tumor should be carefully managed when invade to the internal auditory canal and dura to reduce postoperative recurrence.