ENDOLYMPHATIC SAC TUMORS - RADIOLOGIC APPEARANCE

PURPOSE: To evaluate the radiologic appearance of endolymphatic sac tumors (ELSTs). MATERIALS AND METHODS: Four patients with ELST underwent computed tomography (CT), and two of the four also underwent magnetic resonance (MR) imaging. Their radiologic studies were reviewed for characteristic findings of ELST. RESULTS: Retrolabyrinthine bone destruction was centered at the external aperture of the vestibular aqueduct in all four patients. CT showed irregular bone margins and prominent intratumoral bone in all four patients. At MR imaging, one tumor was almost homogeneous and isointense to gray matter with T1 weighting, and the other was heterogeneous and contained hyper-, hypo-, and isointense foci with T1 and T2 weighting. CONCLUSION: These radiologic changes may help distinguish ELSTs from other tumors of the temporal bone and posterior fossa.