What is the best way to investigate a 65-year-old male with mild intermittent urinary flow reduction, normal Prostate-Specific Antigen (PSA) studies, and an ultrasound showing an enlarged median lobe of the prostate?

Best Investigation for Enlarged Median Lobe with Mild LUTS

Cystoscopy (Option D) is the best investigation for this patient because the enlarged median lobe identified on ultrasound requires direct endoscopic visualization to guide treatment planning, as the anatomical configuration of the prostate—specifically median lobe presence—critically determines which therapeutic options will be effective.

Rationale for Cystoscopy

The presence of an enlarged median lobe is a specific anatomical finding that mandates cystoscopy for treatment planning. 1

• Direct endoscopic visualization provides superior assessment of intravesical protrusion and configuration compared to imaging alone, which is essential when anatomical variants like median lobes are present 1
• The shape and configuration of the prostate as assessed by cystoscopy predicts response to minimally invasive and surgical therapies, including transurethral incision of the prostate, thermotherapy, and other procedures 1
• Median lobe anatomy specifically impacts the choice between transurethral resection versus transurethral incision of the prostate, making direct visualization necessary 1
• The success of certain minimally invasive treatments depends specifically on whether a median lobe is present, so this anatomical detail must be confirmed and characterized endoscopically 1

Why Other Options Are Inappropriate

Annual Renal Function Monitoring (Option A)

• Routine renal function monitoring is not indicated in this patient who has mild symptoms, normal PSA, and no evidence of upper tract involvement 2
• Renal function testing would only be warranted if there were signs of significant obstruction, hydronephrosis, or azotemia—none of which are present here 3

Periodic PSA Measurement (Option B)

• PSA measurement is not sufficient for managing benign prostatic hyperplasia with known anatomical abnormalities 1
• The PSA is already normal, and anatomical assessment—not PSA monitoring—is necessary for treatment planning when a median lobe has been identified 1
• Normal PSA suggests benign prostatic hyperplasia rather than prostate cancer, making serial PSA measurements unnecessary at this juncture 2

Beta-blocker Therapy (Option C)

• This appears to be a distractor option, as alpha-blockers (not beta-blockers) are the first-line medical therapy for lower urinary tract symptoms 2
• However, even alpha-blocker therapy should not be initiated without first characterizing the median lobe anatomy, as treatment success depends on anatomical configuration 1

Clinical Context and Pitfalls

A critical pitfall to avoid is assuming that ultrasound findings alone are sufficient for treatment planning. While ultrasound identified the enlarged median lobe, it cannot provide the detailed anatomical information needed to select appropriate therapy 1

• Giant median lobe enlargement can present with relatively mild symptoms initially but may pose diagnostic challenges and require specific surgical approaches 4
• The median lobe may cause intravesical protrusion that is best assessed endoscopically, particularly when planning minimally invasive procedures 1
• Treatment planning for benign prostatic hyperplasia must consider the anatomical configuration of the prostate, and endoscopy is specifically recommended when treatment alternatives depend on this configuration 1

Treatment Planning Algorithm

Once cystoscopy is performed:

1. Characterize the median lobe: Assess size, degree of intravesical protrusion, and configuration 1
2. Select appropriate therapy: Based on endoscopic findings, choose between transurethral resection, transurethral incision, or minimally invasive procedures 1
3. Consider symptom severity: While symptoms are currently mild, the anatomical findings will guide whether watchful waiting or intervention is appropriate 2

The endoscopic appearance helps guide the choice of therapy in patients who have decided to proceed with an invasive approach, making cystoscopy the essential next step in this patient's evaluation. 1