# Prostate Histology > Prostate histology for MBBS Anatomy: tubuloalveolar glands, peripheral central transition zones, PSA and citrate secretion, corpora amylacea, surgical capsule. - Canonical URL: https://prepelephant.com/topics/mbbs/anatomy/prostate-histology - Exam / course: MBBS · Subject: Anatomy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Prostate Histology", PrepElephant, https://prepelephant.com/topics/mbbs/anatomy/prostate-histology ## Direct answer Zone anatomy predicts prostate disease: this fibromuscular gland of tubuloalveolar (tubuloacinous) secretory units is organised into a peripheral zone (about 70 per cent of gland tissue, the favourite seat of carcinoma and the zone a digital rectal examination actually palpates), a central zone (about a quarter, encircling the ejaculatory ducts near the base), and a transition zone (5-10 per cent around the proximal urethra, where nodular hyperplasia — BPH — grows). The epithelium is simple to pseudostratified columnar resting on a distinctly cellular stroma of smooth muscle and fibroblasts that contracts at ejaculation under sympathetic control. Its secretions — PSA, acid phosphatase, citrate, zinc and fibrolysin — make the semen, and lamellated prostatic concretions (corpora amylacea) accumulate in the acini with age. ## What you must remember - **Gland architecture:** compound tubuloalveolar glands in three concentric groups — periurethral mucosal glands (small, medial), transition-zone (submucosal) glands, and the main peripheral (principal) glands — all opening into the prostatic sinuses beside the urethral crest. - **Zone statistics:** peripheral roughly 70-75 per cent of glandular volume (carcinoma's home), central about 25 per cent (relatively disease-resistant), transition 5-10 per cent (BPH's home) — the numbers examiners quote. - **Epithelium and secretion:** simple or pseudostratified columnar cells secrete PSA (a serine protease liquefying the coagulum), prostatic acid phosphatase, citric acid, zinc (an antimicrobial factor) and fibrolysin — the alkaline milky fluid forms a substantial fraction of semen volume. - **Stroma:** smooth muscle and connective tissue contract at orgasm via sympathetic alpha-1 receptors — the pharmacological target of tamsulosin. - **Corpora amylacea:** rounded, lamellated prostatic concreties in acini, increasing with age and sometimes calcifying — a histology identification favourite. - **Embryological origin:** endodermal outpouchings of the pelvic urethra (urogenital sinus) induced by surrounding mesenchyme under dihydrotestosterone — the mesenchyme instructs, the epithelium buds. - **Clinical anatomy of the zones:** BPH in the transition and periurethral glands compresses the peripheral zone into a false "surgical capsule" — the plane of enucleation; carcinoma arises in the peripheral zone, felt posteriorly and laterally on rectal examination. ## Why two diseases of one gland sit in different corners Begin with the surgical capsule, the histology ward's best-kept teaching secret. As transition-zone and periurethral glands enlarge in benign prostatic hyperplasia, they squeeze the normal peripheral zone outward against the true capsule; the compressed rim is the "surgical capsule," and an open simple prostatectomy shells the adenoma out along it, leaving peripheral tissue behind — which is why a man can develop carcinoma after BPH surgery: the cancer-prone zone was never removed. Histologically, BPH is stromal and glandular hyperplasia in discrete nodules; carcinoma is typically a posterior, peripheral-zone glandular neoplasm with stromal invasion. Drug therapy mirrors the two tissues. Alpha-1 blockers relax the stroma's smooth muscle (symptom relief without size change); 5-alpha-reductase inhibitors starve the gland of dihydrotestosterone and shrink hyperplastic tissue over months — the combination for larger glands. Transurethral resection cuts through the transition zone from within the urethra; systematic biopsy, guided by transrectal ultrasound, samples the peripheral zone where the cancers live, and the apex — where the peripheral zone wraps lowest — is the margin surgeons fear. ## Where students slip The classic slips are numerical and directional. "Posterior lobe hypertrophy obstructs urine" is wrong twice: lobes are anatomical fictions for BPH's territory, and the posteriorly-placed peripheral zone is where cancer, not hyperplasia, grows. The second is assigning the stroma a passive role — half the gland's volume and the entire target of alpha-blockade is muscle and fibroblast. The third is forgetting the prostatic urethra's landmarks: the urethral crest with its verumontanum, where the ejaculatory ducts and the prostatic utricle open — the histology slide's midline clue and the embryology question in disguise. ## Frequently asked questions ### Which prostatic zone gives rise to carcinoma? The peripheral zone, about 70-75 per cent of the gland's tissue — palpable on digital rectal examination as a hard nodule in the posterior or lateral lobes. ### In which zone does benign prostatic hyperplasia develop? The transition zone and periurethral mucosal glands, whose growth compresses the peripheral zone into the surgical capsule. ### What is the surgical capsule of the prostate? The compressed peripheral-zone tissue around an enlarging hyperplastic adenoma — the plane along which enucleation procedures remove the BPH nodule. ### What does prostatic secretion contain? PSA, prostatic acid phosphatase, citrate, zinc and fibrolysin in an alkaline milky fluid that liquefies the semen coagulum and buffers vaginal acidity. ### How does the prostate contract during ejaculation? Sympathetic stimulation of alpha-1 receptors on the abundant smooth-muscle stroma — the same receptor tamsulosin blocks to relax the obstructing gland.