Temporal bone histopathological study of Noonan syndrome

Four temporal bone specimens, obtained from three individuals 1-6 years of age with Noonan syndrome (NS), were studied histopathologically. All four s pecimens were accompanied by similar inner ear abnormalities including the reduced number of spiral ganglion cells, enlarged lateral semicircular cana l, and dislocated endolymphatic sac and vestibular aqueduct. The mean popul ation of spiral ganglion cells (15 699 cells) was approximately half of tho se (32 978 cells) in four age-matched control cases. In addition, they had several middle ear abnormalities including the remaining mesenchyme and deh iscence of the facial canal. To our knowledge, this is the first report to describe the histopathological temporal bone findings in patients with NS. We discuss the implications of the observed abnormalities with regard to cl inical issues. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.