Which of the following is the primary pathological process in benign prostatic hyperplasia?

Explanation

## Pathology of Benign Prostatic Hyperplasia **Key Point:** BPH is characterized by nodular hyperplasia of both stromal (smooth muscle and fibroblasts) and epithelial (glandular) components of the prostate. ### Histological Features - Hyperplasia occurs predominantly in the **transition zone** (periurethral glands) - Both smooth muscle and glandular epithelium proliferate - Results in increased stromal-to-epithelial ratio over time - Nodules compress the urethra, causing obstruction ### Pathogenesis 1. Age-related increase in DHT (dihydrotestosterone) sensitivity 2. Increased expression of androgen receptors in stromal cells 3. Enhanced growth factor signaling (FGF, TGF-β) 4. Reduced apoptosis of prostatic cells 5. Progressive nodular enlargement **High-Yield:** The transition zone hyperplasia is what causes lower urinary tract symptoms (LUTS), not the peripheral zone. This is why a large prostate on DRE may not always correlate with symptom severity. **Clinical Pearl:** BPH is a benign condition and does NOT increase the risk of prostate cancer, though both conditions may coexist in the same patient. ### Distinction from Other Conditions | Feature | BPH | Prostate Cancer | Prostatitis | |---------|-----|-----------------|-------------| | Pathology | Nodular hyperplasia | Malignant transformation | Inflammation ± infection | | Onset | Gradual, age-related | Variable | Acute or chronic | | PSA elevation | Mild to moderate | Marked elevation | Mild elevation | | Histology | Benign glands | Malignant cells | Inflammatory infiltrate |