What is the most appropriate next step in evaluating and managing a 78‑year‑old man with a known bladder diverticulum and a newly discovered 4.6 cm cystic lesion adjacent to the right bladder wall?

Management of 78-Year-Old Male with Bladder Diverticulum and 4.6 cm Cystic Structure

The most appropriate next step is to perform cystoscopy with biopsy of the diverticulum and cystic lesion, combined with cross-sectional imaging (CT urography or MRI) to definitively characterize the cystic structure and rule out malignancy within the diverticulum, as bladder diverticula harbor a significant risk of urothelial carcinoma that requires aggressive evaluation. 1, 2

Immediate Diagnostic Priorities

Endoscopic Evaluation

• Cystoscopy with targeted biopsies of both the diverticulum and the adjacent cystic structure is mandatory to exclude malignancy, as bladder diverticula lack a muscular layer and are prone to harboring occult carcinoma that may be understaged 1, 2, 3
• Multiple selective and random biopsies should be obtained from the diverticulum neck, walls, and any suspicious areas, as the absence of muscularis propria in diverticula makes them high-risk sites for tumor development 1
• Perform examination under anesthesia to assess for palpable masses or fixation, which would indicate more advanced disease 1

Cross-Sectional Imaging

• CT urography or MRI urogram is essential to characterize the 4.6 cm cystic structure, determine its relationship to the bladder and diverticulum, assess for upper tract involvement, and evaluate for lymphadenopathy 1, 4
• Imaging should specifically evaluate whether the cystic structure represents a second diverticulum, a urachal remnant, or a separate pathologic entity 2, 4
• Retrograde cystography may be performed if the relationship between the cystic structure and bladder remains unclear after initial imaging 2, 3

Critical Diagnostic Considerations

Malignancy Risk Assessment

• Bladder diverticula carry a 2-10% risk of harboring urothelial carcinoma, which is often diagnosed at advanced stages due to the absence of a muscular layer allowing early extravesical extension 2, 3
• The presence of a large (4.6 cm) adjacent cystic structure raises concern for either a second diverticulum (which would increase malignancy risk) or a separate pathologic process requiring definitive characterization 2, 4
• If high-grade or invasive disease is identified on biopsy, proceed directly to staging with chest/abdomen/pelvis CT and consideration for radical cystectomy with pelvic lymphadenectomy 1

Bladder Outlet Obstruction Evaluation

• Assess for benign prostatic hyperplasia or other causes of outlet obstruction, as these are the underlying etiology in most elderly men with acquired diverticula 3, 5
• Measure post-void residual volume and consider urodynamic studies if outlet obstruction is suspected, as relief of obstruction may be necessary regardless of diverticulum management 3, 5
• Prostate-specific antigen (PSA) should be obtained to screen for concurrent prostatic pathology 5

Management Algorithm Based on Findings

If Malignancy is Identified

• For high-grade Ta, T1, or Tis within the diverticulum: Radical cystectomy with bilateral pelvic lymphadenectomy is strongly preferred over diverticulectomy alone, as the lack of muscular layer precludes adequate oncologic resection 1
• For muscle-invasive disease (≥T2): Strongly consider neoadjuvant cisplatin-based combination chemotherapy (Category 1) followed by radical cystectomy with extended lymphadenectomy 1, 6
• Partial cystectomy or diverticulectomy alone is contraindicated for malignancy within diverticula due to inadequate margins and high recurrence rates 1

If No Malignancy is Found

• For large symptomatic diverticula (>5 cm) causing recurrent infections, stones, or incomplete emptying: Open or laparoscopic diverticulectomy is indicated after addressing any bladder outlet obstruction 2, 3, 7
• For small asymptomatic diverticula: Observation with relief of outlet obstruction (e.g., transurethral resection of prostate) may be sufficient 3, 5
• Surveillance cystoscopy every 6-12 months is mandatory for conservatively managed diverticula due to ongoing malignancy risk 1, 2

Common Pitfalls to Avoid

• Never assume a cystic pelvic structure is benign without tissue diagnosis, particularly in elderly men with bladder pathology, as bladder diverticula can mimic ovarian cysts or other benign lesions on imaging 4
• Do not perform diverticulectomy without first ruling out malignancy, as inadequate oncologic resection of occult carcinoma leads to poor outcomes 2, 3
• Ensure adequate biopsy sampling includes muscle when possible, as absence of muscularis propria in specimens occurs in 49% of cases and leads to understaging 1, 8
• Do not delay definitive treatment beyond 3 months if malignancy is confirmed, as surgical delays are associated with inferior survival 6