title: Endolymphatic sac tumor with overexpression of V2 receptor mRNA and inner ear hydrops.
abstract: CONCLUSIONS
  We reported previously that hyperactivation of vasopressin type-2 receptor (V2R)-mediated signaling in the endolymphatic sac could affect endolymphatic fluid metabolism, resulting in the pathogenesis of endolymphatic hydrops. Taken together with the present endolymphatic sac tumor (ELST) study, it is suggested that disorder of V2R signaling in the endolymphatic sac for any reason could be involved in the pathogenesis of endolymphatic hydrops. Although it is due to tumor genesis in ELST, it is idiopathic in nature in Meniere's disease.
  
  
  OBJECTIVE
  We encountered two cases of ELST showing Meniere's disease-like symptoms. Both cases were suspected of having endolymphatic hydrops using neuro-otological examinations. To clarify the histopathological diagnosis of ELST and the molecular pathogenesis of endolymphatic hydrops, we performed histopathological and molecular biological examinations of the endolymphatic sac.
  
  
  METHODS
  ELSTs in two rare cases were removed completely through the transmastoidal approach. V2R mRNA expression was examined using real-time PCR.
  
  
  RESULTS
  The first case was diagnosed as inflammatory granulation adjacent to the endolymphatic sac, i.e. pseudo-ELST, and the second case was diagnosed as papillary adenoma of ELST. V2R mRNA expression was up-regulated in the endolymphatic sac of both cases as seen in Meniere's disease compared with controls.
authors.affiliation: Department of Otolaryngology, Osaka University, School of Medicine, Japan. tkitahara@ent.med.osaka-u.ac.jp
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kitahara
authors.forename: Chie
authors.initials: C
authors.lastname: Maekawa
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kizawa
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kamakura
authors.forename: Arata
authors.initials: A
authors.lastname: Horii
authors.forename: Hidenori
authors.initials: H
authors.lastname: Inohara
mesh_terms: D000236:Adenoma / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D000328:Adult; D001301:Audiometry, Pure-Tone; D003937:Diagnosis, Differential; D004428:Ear Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D018159:Endolymphatic Hydrops / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D004712:Endolymphatic Sac / Q000473:pathology / Q000601:surgery; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D006104:Granuloma, Plasma Cell / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008416:Mastoid / Q000601:surgery; D008575:Meniere Disease / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis / Q000235:genetics / Q000473:pathology / Q000601:surgery; D009481:Neurophysins / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D014057:Tomography, X-Ray Computed; D014667:Vasopressins / Q000235:genetics*; D015837:Vestibular Diseases / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000601:surgery
chemical_list: C438657:AVP protein, human; D009481:Neurophysins; D011498:Protein Precursors; D012333:RNA, Messenger; D014667:Vasopressins