Morphogenesis of nodular hyperplasia--prostate.

Step-section study was done on 161 prostates from medicolegal autopsies. Nodular hyperplasia occurred in 35-year-old subjects but increased in frequency with advancing age. Nodular hyperplasia originates as an early stromal nodule usually by the side of urethra. This nodule perhaps stimulates the duct in its close vicinity to proliferate and to bud into the solid nodule. Thereafter, stromal and epithelial elements proliferate to form either a glandular or a mixed nodule. A leiomyomatous nodule has been interpreted as a unilateral differentiation and maturation of stromal nodule to smooth muscle.