title: Role of PAX-8, CD5, and CD117 in distinguishing thymic carcinoma from poorly differentiated lung carcinoma.
abstract: OBJECTIVE
  To determine if PAX-8, CD5, and CD117 can differentiate thymic carcinoma from poorly differentiated lung carcinoma.
  
  
  METHODS
  Archived cases of thymic (n=13) and poorly differentiated lung (n=15) carcinoma were analyzed for intensity and proportion of expression of PAX-8, CD117, and CD5.
  
  
  RESULTS
  PAX-8 was positive in 69.2% of thymic and 5.8% of lung carcinomas. CD117 was positive in 84% of thymic and 26.6% of lung carcinomas. A total of 53% of thymic and none of the lung carcinomas were positive for CD5. Forty-six percent, 53%, and 69% of thymic carcinomas were dual positive for combinations of CD5/PAX-8, CD117/CD5, and CD117/PAX-8, respectively. None of the lung carcinomas were dual positive. Positivity for any 2 of the 3 markers was seen in 84% of thymic and none of the lung carcinomas. Triple positivity was seen in 53% of thymic carcinomas.
  
  
  CONCLUSIONS
  Adding PAX-8 to CD117 and CD5 increases the diagnostic yield for thymic carcinoma.
authors: Department of Pathology, North Shore-Long Island Jewish Health System, NY.
authors: Jaya R
authors: JR
authors: Asirvatham
authors: Michael J
authors: MJ
authors: Esposito
authors: Tawfiqul A
authors: TA
authors: Bhuiya
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D018956:CD5 Antigens / Q000378:metabolism*; D002277:Carcinoma / Q000175:diagnosis*; D002454:Cell Differentiation; D003429:Cross Reactions; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis*; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism*; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism*; D013953:Thymus Neoplasms / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D018956:CD5 Antigens; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors; D019009:Proto-Oncogene Proteins c-kit