A 68-year-old man from Mumbai presents with progressive lower urinary tract symptoms for 6 months: nocturia (×4 per night), weak urinary stream, and incomplete emptying. Digital rectal examination reveals a smooth, firm, enlarged prostate without nodules. PSA is 2.8 ng/mL. Transrectal ultrasound shows diffuse glandular enlargement. Urinalysis is normal. What is the most likely pathological diagnosis?