Evaluation of mucinous metaplasia of the prostate gland by mucin histochemistry

Objective. To evaluate the presence of mucinous metaplasia in normal and benign hyperplastic prostates, using stains for neutral and acidic mucins. Patients, materials and methods. Normal prostate glands were removed during the post-mortem examination of 11 consecutive subjects (median age 45 years, range 17-79) who had died accidentally. Specimens were also obtained from 10 patients (median age 70.2, range 61-82) undergoing suprapubic prostatectomy for prostatic hyperplasia. The specimens were examined histologically; sections were stained using the periodic acid-Schiff (PAS) method for neutral mucins and the alcian blue (AB) method at pH 2.5 for acidic mucins. The positive sections were also immunostained for high molecular weight cytokeratin (KER), and prostate-specific antigen (PSA) using the strept-avidin-biotin (SAB) method. Results Mucinous metaplasia was found in six of the normal prostates and in three of the hyperplastic glands. Usually. the cells were tall columnar, containing both AB- and PAS-positive material. The cells were negative both for PSA and KER. Mucinous metaplasia affected all ages, including a 17-year-old, and mostly involved the inferior periurethral area. Conclusion. Benign mucinous metaplasia was more frequent than previously appreciated, involved all ages, was mainly periurethral and did not correlate with the usual distribution of adenocarcinoma of the prostate.