title: Spatial distribution of nerve fiber pathology and vasculitis in microscopic polyangiitis-associated neuropathy.
abstract: We analyzed the 3-dimensional distribution of pathologic findings in 8 autopsied cases of neuropathy associated with microscopic polyangiitis. Necrotizing vasculitis was commonly and diffusely present in the epineurium of the sciatic/tibial and median nerves. Although findings of vasculitis were distributed diffusely in proximal to distal segments of the nerve trunks, marked loss of myelinated fibers occurred only from the middle to distal segments of these nerves. Neurons of the sensory and sympathetic ganglia were well preserved, as were myelinated fibers of the anterior and posterior spinal roots. Central fascicular nerve fiber degeneration, suggesting direct ischemic damage, occurred in restricted segments of the proximal-middle portion of the sciatic/tibial and median nerve trunks. Vasculitis was also seen in various visceral organs in all patients, but its distribution differed among individual patients; the severity of vasculitis in the other organs did not correlate with that in the peripheral nerves. The distinct spatial distribution pattern of nerve fiber degeneration, in contrast to the ubiquitous presence of vasculitis, suggested that the ischemic zone that directly damages nerve fibers is present in the proximal-middle portion of peripheral nerve trunks in microscopic polyangiitis.
authors.affiliation: Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Morozumi
authors.forename: Haruki
authors.initials: H
authors.lastname: Koike
authors.forename: Minoru
authors.initials: M
authors.lastname: Tomita
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kawagashira
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iijima
authors.forename: Masahisa
authors.initials: M
authors.lastname: Katsuno
authors.forename: Naoki
authors.initials: N
authors.lastname: Hattori
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tanaka
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D055953:Microscopic Polyangiitis / Q000150:complications / Q000473:pathology*; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009422:Nervous System Diseases / Q000150:complications / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology*; D014657:Vasculitis / Q000150:complications / Q000473:pathology*