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
Siroth Noiwan MD*, Samrerng Rattanarapee MD*
Affiliation : * Department of Pathology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
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 of the 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 Departmeant 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.
Material and Method: The present study is a retrospective study of 190 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 of prostatic 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 different special histochemical stains for acid mucin. Among these, 167 cases (88%) were positive for mucicarmine, 157
(83%) cases were positive for Alcian blue at pH 2.5, and 173 cases (91%) were positive for colloidal iron. All 177 cases were
positive for PSA immunohistochemical stain.
Conclusion : 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.
Keywords : Prostatic adenocarcinoma, Intraluminal acid mucin, Radical prostatectomy, Core biopsy, Mucicarmine histochemical stain, Alcian blue at pH 2.5 histochemical stain, Colloidal iron histochemical stain, PSA immunohistochemical stain
