Benign prostatic hyperplasia first develops in the

Benign prostatic hyperplasia arises from submucosal glands of periurethral transitional zone with stromal proliferation and adenosis forming a nodular enlargement. It eventually compresses the peripheral zone glands into a false capsule and causes the appearance of typical 'lateral' lobes. Reference : page1345 Bailey and Love's sho practice of surgery 25th edition