title: Mucin production in prostatic adenocarcinoma: a retrospective study of 190 radical prostatectomy and/ or core biopsy specimens in department of pathology, Siriraj Hospital, Mahidol University, Thailand.
abstract: BACKGROUND
  Diagnoses of prostatic adenocarcinoma are made based on a constellation of architectural, cytological, and ancillary findings, which include intraluminal mucin secretion. Several studies have shown that luminal acid mucin is frequently present in prostatic adenocarcinoma. Immunohistochemical stain (immunostaining) becomes extremely helpful in the diagnosis of prostatic adenocarcinoma, especially in doubtful cases. However, presently, the technique is not available in most hospitals, particularly in the regional or provincial areas. Thus, luminal acid mucin and its detection by histochemical stains may be one ofthe useful tools in diagnosing prostatic adenocarcinoma.
  
  
  OBJECTIVE
  To determine the percentage of mucin production in prostatic adenocarcinoma from 190 radical prostatectomy and/or core biopsy specimens in the Department of Pathology, Siriraj Hospital, Mahidol University to compare the percentage of positivity among three different special histochemical stains (mucicarmine, Alcian blue at pH 2.5, and colloidal iron), and to determine the PSA-expression among the prostatic adenocarcinoma that produces mucin by immunohistochemical technique.
  
  
  METHODS
  The present study is a retrospective study of190 cases that were diagnosed as prostatic adenocarcinoma (with any Gleason's microscopic pattern) from radical prostatectomy and/or core biopsy specimens in Department of Pathology, Siriraj Hospital, Mahidol University between January 2006 and May 2007. All cases were retrieved from a computer filing system of the Department. All H&E slides that contained diagnostic materials were reviewed and stained with all three different special histochemical stains. Positive cases were subsequently studied to find PSA expression by means of immunohistochemical study. Cases with microscopic variants ofprostatic adenocarcinoma and metastasis were excluded.
  
  
  RESULTS
  One hundred and seventy seven cases (93%) of these prostatic adenocarcinomas were positive for at least one of three diferent special histochemical stains for acid mucin. Among these, 167 cases (88%) were positive for mucicarmine, 157 (83%) cases were positive for Alcian blue at pH2.5, and 173 cases (91%) were positive for colloidal iron. All 177 cases were positive for PSA immunohistochemical stain.
  
  
  CONCLUSIONS
  Intraluminal acid mucin and its detection by special histochemical stains is one of the useful methods (with a high percentage of positivity) in diagnosing prostatic adenocarcinoma in association with other architectural and cytological criteria. Mucicarmine and colloidal iron stains appear to be more useful than Alcian blue at pH 2.5 stain according to their positivity percentage. However in pathologic practice, mucicarmine stain is more commonly used than colloid iron stain due to the difficulty in preparation and interpretation of the latter There is no correlation between mucin production and PSA expression in prostatic adenocarcinoma but PSA immunohistochemical stain is still useful to confirm the prostatic origin of poorly differentiated carcinomas or metastatic lesions.
authors.affiliation: Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Siroth
authors.initials: S
authors.lastname: Noiwan
authors.forename: Samrerng
authors.initials: S
authors.lastname: Rattanarapee
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D000951:Antigens, Neoplasm / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001706:Biopsy; D006785:Hospitals, University; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009077:Mucins / Q000378:metabolism*; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D013194:Staining and Labeling; D013785:Thailand
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D009077:Mucins; D017430:Prostate-Specific Antigen