title: Pulmonary tumor thrombotic microangiopathy: a clinical analysis of 30 autopsy cases.
abstract: OBJECTIVE
  Pulmonary tumor thrombotic microangiopathy (PTTM) is a unique, rare and fatal form of pulmonary arterial tumor embolism. The aim of this study was to evaluate the clinical characteristics and pathological and immunohistochemical findings of PTTM.
  
  
  METHODS
  Autopsy records dated between January 1983 and May 2008 in our hospital were reviewed, and those of patients who died from pulmonary tumor embolism resulting from malignant neoplasm were retrieved. The relevant tissue slides were reevaluated and examined immunohistochemically to confirm the diagnosis.
  
  
  RESULTS
  Among 2,215 consecutive autopsy cases of carcinoma, 30 patients (1.4%) were diagnosed with definitive PTTM. The common symptom was progressive dyspnea. A hypercoagulative state was observed in all measured cases (n = 21). The chest computed tomography findings (n = 6) included consolidation, ground-glass opacity, small nodules and a tree-in-bud appearance. Perfusion scans were performed in seven patients, six of whom demonstrated multiple small defects. The median survival time after the initiation of oxygen supplementation was nine days. The most frequent primary site was the stomach (n = 18 ; 60%) , and the most frequent histological type was adenocarcinoma (28/30 ; 93.3%) . The immunohistochemical findings for tumor cells located within the tumor emboli were positive for vascular endothelial growth factor (28/29 ; 96.6%) and tissue factor (29/29 ; 100%).
  
  
  CONCLUSIONS
  Clinicians should suspect PTTM in cancer patients who exhibit acute worsening respiratory insufficiency accompanied by a hypercoagulative state without embolism in major pulmonary arteries. The PTTM patients evaluated in our study had very poor prognoses. Vascular endothelial growth factor and tissue factor may play important roles in PTTM.
authors.affiliation: Department of Respiratory Medicine, Respiratory Center, Toranomon Hospital, Japan. uruga.hironori@gmail.com
authors.forename: Hironori
authors.initials: H
authors.lastname: Uruga
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujii
authors.forename: Atsuko
authors.initials: A
authors.lastname: Kurosaki
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hanada
authors.forename: Hisashi
authors.initials: H
authors.lastname: Takaya
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Nasa
authors.initials: N
authors.lastname: Morokawa
authors.forename: Sakae
authors.initials: S
authors.lastname: Homma
authors.forename: Kazuma
authors.initials: K
authors.lastname: Kishi
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001344:Autopsy; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011379:Prognosis; D011651:Pulmonary Artery; D011655:Pulmonary Embolism / Q000175:diagnosis / Q000473:pathology*; D013274:Stomach Neoplasms / Q000175:diagnosis; D057049:Thrombotic Microangiopathies / Q000175:diagnosis / Q000473:pathology*