Transotic Approach for Resection of Expansile Endolymphatic Sac Tumor

Objectives and Design Endolymphatic sac tumors (ELSTs) are rare and indolent tumors that arise from the endolymphatic sac in the posterior petrous ridge. We present a video case report illustrating the use of a transotic approach for resection of an expansile ELST. Setting and Participants  A 25-year-old male presented with a multiyear history of worsening left-sided hearing loss, vertigo, and headaches. Otoscopy revealed a red mass behind an intact tympanic membrane. Computed tomography revealed a large, locally aggressive mass centered in the posterior petrous temporal bone. Magnetic resonance imaging demonstrated a heterogeneously enhancing 2.4 × 3.1 × 2.4 cm tumor that exerted mass effect on the cerebellar surface with extension into the jugular foramen, tympanic cavity, internal auditory canal, and cistern of the cerebellopontine angle. A transotic approach was planned to obtain the necessary generous exposure. Main Outcome Measures and Results  Preoperative angiography revealed arterial supply via the ascending pharyngeal and tumor embolization with Onyx was performed. Surgical resection began with a blind-sac closure created from the external auditory canal. The tympanic membrane and malleus were removed and the incustapedial joint was transected. A subtotal petrosectomy was performed for partial tumor exposure. The facial canal and sigmoid sinus were carefully skeletonized and a labrynthectomy was performed. The tumor was resected using a combination of bipolar cautery and blunt and sharp dissection. For closure, an abdominal fat graft was secured with overlying resorbable mesh followed by sequential closure of all skin layers. Histopathologic analysis revealed an ELST. Conclusion  The transotic approach offers wide exposure and facilitates large, complex tumor removal. The link to the video can be found at https://youtu.be/YvhyN8iVi44 .