title: Use of polarized light microscopy is essential in the efficient diagnosis of respiratory amyloidosis and could decrease disease prevalence.
abstract: BACKGROUND
  Primary tracheobronchial amyloidosis (TBA) is a rare disease of unknown etiology, with a high misdiagnosis rate. The current gold standard diagnostic criteria require double-positive results for Congo red staining and polarized light microscopy examination.
  
  
  OBJECTIVE
  The aim of the present report was to examine the diagnostic value of polarized light microscopy in TBA diagnosis in China.
  
  
  METHODS
  Thirteen cases from the Shandong University Qilu Hospital were reviewed. Polarized light microscopic examination was conducted after searching for cases with positive Congo red staining.
  
  
  RESULTS
  Among the 13 patients, eight displayed yellow-green birefringence body with polarized light microscopic examination. This result indicated a false-positive rate of 38.5% with Congo red staining used as the single criteria for TBA diagnosis. After reviewing the Chinese literature and selecting 104 reported cases of TBA in China, we found that diagnosis with the gold standard was confirmed in <30% patients, which may lead to misdiagnosis and delayed treatment.
  
  
  CONCLUSIONS
  The universal use of polarized light microscopy in China is currently limited, and there is a big gap from the international diagnosis standards. There is a need to include polarized light microscopy in routine TBA diagnosis to reduce the misdiagnosis rate, and achieve optimal treatment.
authors.affiliation: Department of Respiratology, Qilu Hospital Shandong University, Jinan, China.
authors.forename: Dedong
authors.initials: D
authors.lastname: Ma
authors.affiliation: Department of Anaesthesiology, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China.
authors.forename: Hongxiu
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of Respiratology, Qilu Hospital Shandong University, Jinan, China.
authors.forename: Cuijuan
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of ICU, Ningbo Peoples Hospital, Ningbo, China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Ying
authors.affiliation: Department of Respiratology, Qilu Hospital Shandong University, Jinan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
mesh_terms: D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D003224:Congo Red / Q000592:standards; D003951:Diagnostic Errors; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D000075363:Immunoglobulin Light-chain Amyloidosis / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008859:Microscopy, Polarization / Q000295:instrumentation*; D008875:Middle Aged; D015995:Prevalence; D012140:Respiratory Tract Diseases / Q000473:pathology*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D003224:Congo Red
keywords: amyloidosis - Congo red staining - diagnosis - false-positive - polarized light microscopy