Cystitis Cystica

Cystitis cystica is a benign proliferative lesion of the bladder mucosa in which von Brunn nests of urothelium lie under the epithelium and form fluid filled cysts.

It is common and often incidental, found in a substantial share of otherwise normal bladders at autopsy.

It is associated with chronic irritation from recurrent infection, outlet obstruction, stones, indwelling catheters, neurogenic bladder, previous radiotherapy and pelvic lipomatosis.

It occurs at any age, and in women and children it affects the trigone and bladder neck most. It has no proven malignant potential.

Pathophysiology. Chronic irritation causes urothelial hyperplasia, with nests that sink into the lamina propria and degenerate centrally into cysts. When glandular change affects the nests, the picture becomes cystitis glandularis.

Most patients have no symptoms. Others report frequency, urgency, dysuria, suprapubic discomfort, haematuria and recurrent urinary infection. In children, it follows recurrent infection or anatomical abnormality. Symptoms usually reflect the underlying cause rather than the cysts.

• Urinalysis and culture, ideally on at least 2 samples, plus creatinine.
• Renal and bladder ultrasound, which may show cysts as small filling defects or wall thickening, with residual urine measurement.
• Uroflowmetry and post-void residual to detect obstruction.
• Cystoscopy: multiple translucent, grape like cysts 2 to 5 mm across, often with a vascular halo, most frequent on the trigone and bladder neck.
• Biopsy only for atypical or papillary looking areas, persistent haematuria or uncertainty.

Differential diagnosis.

• Cystitis glandularis
• Papillary urothelial carcinoma or carcinoma in situ
• Ureterocele
• Interstitial cystitis
• Nephrogenic adenoma
• Tuberculous or schistosomal cystitis
• Malakoplakia

• Asymptomatic lesions need no treatment.
• Treat the cause: relieve outlet obstruction, remove stones, replace or remove long term catheters, and treat infection with culture directed antibiotics.
• Recurrent infection: culture directed treatment of each episode, hydration, and prophylaxis only when episodes recur at least 3 times in 12 months. Options are nitrofurantoin 50 to 100 mg orally at night (avoid when eGFR is under 45, and review for pulmonary and liver toxicity if used long term) or trimethoprim 100 mg orally at night. Review prophylaxis every 3 to 6 months.
• Cystoscopic fulguration or resection is reserved for persistent symptoms with a clear anatomical focus, or for diagnosis.

Monitoring. Symptom review and urine culture at 3 months. Repeat cystoscopy only if haematuria persists, symptoms change, or new papillary lesions appear.

Referral and escalation. Refer to urology for haematuria, retention, outlet obstruction, or lesions that look papillary or atypical.