Clinical features and treatment of endolymphatic sac tumor

Background: Endolymphatic sac tumor (ELST) is an extremely rare disease that does not have established clinical guidelines. Objective: To provide guidance for the diagnosis and management of ELSTs. Methods: We retrospectively reviewed the medical records of patients who were suspected to have a lesion in the location of endolymphatic sac. Seven patients were included. Histopathologic diagnosis confirmed five ELSTs and two other diseases. Results: All of the enrolled patients had hearing impairment. Facial palsy was found in four out of five patients with ELST, whereas none of the patients in other disease group showed facial palsy. CT and MRI findings were consistent with those in previous literatures; however, angiographic findings were not consistent with those previously reported. All patients underwent surgery. Recurrence occurred in two patients with ELST, although there was no visible remnant tumor after the operation. These patients were treated with stereotactic radiosurgery. Conclusion: Hearing impairment and facial palsy were representative symptoms of ELST. All ELSTs showed 'salt and pepper' signal in MRI T1-weighted images, and smaller tumors could have blood supply from AICA in the radiologic study. Complete surgical resection with optional stereotactic radiosurgery should be considered in ELST.