Mucinous glands are associated with ducts (basophilic structures at the top of the lobule) in this example of Cowper's glands. The main differential diagnosis is with foamy gland variant of prostatic adenocarcinoma. Cowper's glands have a lobular architecture as seen here. The cells lining the glands are distended with mucin nearly occluding the lumen. Prostate cancer would have an infiltrative pattern and well-defined open lumens. Distinction from foamy gland variant of prostatic adenocarcinoma can be usually accomplished on H&E stains. In difficult cases, immunostains can be performed. The ductal epithelial cells and the attenuated basal cell layer around the acini strongly stain with high molecular weight cytokeratin.