TY - JOUR T1 - A nationwide survey of hypertrophic pachymeningitis in Japan JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 732 LP - 739 DO - 10.1136/jnnp-2013-306410 VL - 85 IS - 7 AU - Tomomi Yonekawa AU - Hiroyuki Murai AU - Satoshi Utsuki AU - Takuya Matsushita AU - Katsuhisa Masaki AU - Noriko Isobe AU - Ryo Yamasaki AU - Mari Yoshida AU - Susumu Kusunoki AU - Kiyomi Sakata AU - Kiyotaka Fujii AU - Jun-ichi Kira Y1 - 2014/07/01 UR - http://jnnp.bmj.com/content/85/7/732.abstract N2 - Objectives To clarify the prevalence, frequent causes and distinct features of hypertrophic pachymeningitis (HP) according to background conditions in a nationwide survey in Japan. Methods The study began with a preliminary survey to determine the approximate number of HP patients diagnosed from 1 January 2005 to 31 December 2009, and was followed by a questionnaire survey for clinical and laboratory findings. HP was defined as a condition with thickening of the cranial or spinal dura mater with inflammation, evidenced by MRI or histology. Results Crude HP prevalence was 0.949/100 000 population. The mean age at onset was 58.3±15.8 years. Among 159 cases for whom detailed data were collated, antineutrophil cytoplasmic antibody (ANCA)-related HP was found in 54 cases (34.0%) and IgG4/multifocal fibrosclerosis (MFS)-related HP in 14 cases (8.8%). Seventy cases (44.0%) were classified as ‘idiopathic’ and 21 (13.2%) as ‘others’. ANCA-related HP cases showed a female preponderance, a higher age of onset, and higher frequencies of otological symptoms and elevated systemic inflammatory biomarkers, but lower frequencies of diplopia compared with idiopathic HP. IgG4/MFS-related HP cases showed a marked male predominance; all had cranial HP while none had isolated spinal HP or decreased sensation. Conclusions HP is not extremely rare. ANCA-related HP is the most frequent form, followed by IgG4/MFS-related HP. Both forms have unique features, which may help to differentiate background causes. ER -