Adenosis is a lesion of transition zone and is usually seen incidentally in TURP specimens. It is encountered in just under 1% of prostate needle biopsies where it may closely mimic low-grade cancers. At low magnification, this lobular focus of adenosis shows small, crowded glands with pale cytoplasm. Prostate cancer is in the differential diagnosis. See next image for high molecular weight cytokeratin stain.