title: Thrombotic microangiopathy after allogeneic hematopoietic stem cell transplantation: an autopsy study.
abstract: BACKGROUND
  Posttransplantation thrombotic microangiopathy (PTMA) is a complication of allogeneic hematopoietic stem cell transplantation (HSCT). However, limited autopsy data are available, and it remains unclear whether PTMA is a discrete clinical and pathologic entity. The aims of this autopsy study were to determine the correlation between clinical and pathologic diagnosis of PTMA, to define the precise morphologic spectrum of PTMA, and to seek for potential etiologic factors.
  
  
  METHODS
  The study included 20 consecutive patients with HSCT autopsied at the University of Oklahoma, between 1994 and 2005. Applying strict clinical-laboratory criteria, 6 patients were diagnosed clinically with PTMA and treated with plasma exchange. Clinical variables, including underlying disease, conditioning regimen, stem cell donor status, duration and serum level of cyclosporine, infections, and acute graft versus host disease were compared statistically in patients with histologic signs of PTMA (n=8) with those without PTMA (n=12).
  
  
  RESULTS
  PTMA was verified histologically in all 6 patients with a clinical diagnosis of PTMA but only 2 of the 14 patients who were not clinically diagnosed had histologic evidence of PTMA (P<0.0001). Kidneys were affected in all 8 patients with PTMA, and limited extrarenal involvement by PTMA was observed in 3 of these 8 patients. No statistically significant differences in relevant clinical and morphologic variables were identified between the PTMA and non-PTMA groups.
  
  
  CONCLUSIONS
  This study documents a strong correlation between the clinical and morphologic diagnosis of PTMA. The kidney is the primary target of PTMA, with dominant glomerular and arteriolar involvement. The etiology is likely to be multifactorial.
authors.affiliation: Department of Pathology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., Oklahoma City, OK 73190, USA.
authors.forename: Koushan
authors.initials: K
authors.lastname: Siami
authors.forename: Kiarash
authors.initials: K
authors.lastname: Kojouri
authors.forename: Karen K
authors.initials: KK
authors.lastname: Swisher
authors.forename: George B
authors.initials: GB
authors.lastname: Selby
authors.forename: James N
authors.initials: JN
authors.lastname: George
authors.forename: Zoltan G
authors.initials: ZG
authors.lastname: Laszik
mesh_terms: D000293:Adolescent; D000328:Adult; D001344:Autopsy; D002648:Child; D005260:Female; D006086:Graft vs Host Disease / Q000175:diagnosis / Q000473:pathology; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D007668:Kidney / Q000098:blood supply / Q000473:pathology; D008297:Male; D008875:Middle Aged; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology; D014184:Transplantation, Homologous / Q000009:adverse effects