title: Clinical and histopathologic features of 8 patients with microscopic polyangiitis including two with a slowly progressive clinical course.
abstract: BACKGROUND
  Microscopic polyangiitis (MPA) is a systemic antineutrophil cytoplasmic autoantibody-associated vasculitis associated with necrotizing and crescentic glomerulonephritis and pulmonary capillaritis. MPA generally has a rapidly progressive clinical course, but there have been recent reports of slowly progressive cases.
  
  
  OBJECTIVE
  To evaluate the typical cutaneous findings of MPA, we recorded the clinical and histopathologic features of the cutaneous manifestations.
  
  
  METHODS
  Eight patients with MPA, who had presented with cutaneous manifestations between 2001 and 2005 in our department, were retrospectively reviewed. They had necrotizing vasculitis in their cutaneous lesions as confirmed by skin biopsy specimens. Patients with other known connective tissue diseases were not included in the study.
  
  
  RESULTS
  All 8 patients with MPA presented cutaneously with erythematous macules on their extremities. Livedo reticularis (5/8, 68%) was also observed. Six of the 8 patients with MPA were given the diagnosis within 3 months of their initial manifestation. In skin biopsy specimens, necrotizing vasculitis was noted in the reticular dermis to the subcutaneous fat. In contrast, the other two patients with MPA were given the diagnosis about 10 years after their initial manifestation. Histopathologic findings demonstrated necrotizing vasculitis with moderate neutrophilic infiltrations in the papillary to middle dermis in the latter two patients. Serum myeloperoxidase-antineutrophil cytoplasmic autoantibody levels were only moderlately elevated in the latter two patients and they were given the diagnosis of slowly progressive MPA. Histopathologically, palisading granulomas were present on the elbow of one of them.
  
  
  CONCLUSIONS
  The study was based on histopathological analysis in a limited number of patients due to the rareness of the investigated disease.
  
  
  CONCLUSIONS
  There appears to be a correlation between a slowly progressive clinical course of MPA and the depth of dermal involvement and the severity of neutrophilic infiltration in biopsy specimens. Based on these results, we believe that these characteristic patterns may help clinicians establish an earlier diagnosis of possible MPA with positive antineutrophil cytoplasmic autoantibody titers.
authors.affiliation: Department of Dermatology, St Marianna University School of Medicine, Kanagawa, Japan. tami@marianna-u.ac.jp
authors.forename: Tamihiro
authors.initials: T
authors.lastname: Kawakami
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawanabe
authors.forename: Chihiro
authors.initials: C
authors.lastname: Saito
authors.forename: Maya
authors.initials: M
authors.lastname: Kannari
authors.forename: Masako
authors.initials: M
authors.lastname: Mizoguchi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Nagafuchi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okazaki
authors.forename: Shoichi
authors.initials: S
authors.lastname: Ozaki
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kimura
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Soma
mesh_terms: D000328:Adult; D000368:Aged; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood; D018450:Disease Progression; D004890:Erythema / Q000209:etiology / Q000473:pathology; D005121:Extremities; D005260:Female; D006099:Granuloma / Q000209:etiology / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020556:Neutrophil Infiltration; D009195:Peroxidase / Q000097:blood; D010488:Polyarteritis Nodosa / Q000209:etiology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology; D012871:Skin Diseases / Q000209:etiology* / Q000473:pathology*; D017445:Skin Diseases, Vascular / Q000209:etiology / Q000473:pathology; D014657:Vasculitis / Q000097:blood / Q000150:complications* / Q000503:physiopathology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D009195:Peroxidase