Mucinous metaplasia in the prostate gland.

The prostate gland normally secretes neutral mucosubstances that can be detected within the lumina of acini and ducts; adenocarcinomas often produce both acidic and neutral mucins, a feature that has been suggested to be of some diagnostic use. The presence of mucin-filled cells is not, however, a feature of the normal prostate. Over the last few years, we have observed tall, columnar, mucin-secreting cells in a variety of conditions in 12 benign prostates. All cases were stained histochemically for mucin with Mayers' mucicarmine, alcian blue (pH 2.7), and periodic-acid-Schiff with diastase digestion. In four cases, immunoperoxidase stains for prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) were performed. Mucin-secreting cells were found in the foci of sclerotic atrophy (n = 5), transitional cell metaplasia (n = 3), basal cell hyperplasia (n = 2), prostatrophic hyperplasia (n = 1), and nodular hyperplasia (n = 1). In all examples, the cells stained intensely with PAS, mucicarmine, and alcian blue. The cells were nonreactive for PSA and PAP in the cases studied. To our knowledge, the presence of tall, columnar, mucin-secreting cells has not been previously described in atrophy or basal cell hyperplasia. These observations expand our appreciation of the histologies that may be seen in the prostate gland; in addition, the recognition of acidic mucin-secreting cells in benign lesions points to the nonspecificity of this finding in the diagnosis of malignancy.