To describe 5 cases with complete urinary bladder duplication, their associated conditions, and their respective treatment. Urinary bladder duplication is an extremely rare congenital anomaly of the urinary system. So far about 70 cases have been published in the English literature, most of them as case reports and a few case series.

All consecutive patients with bladder duplication treated at our institution between 2000 and 2015 were included. Patient records were retrospectively analyzed, and 5 patients with urinary bladder duplication were identified (see Summary Figure). Two patients were male. All duplications were recognized by health care providers. In 1 case recognition was prenatal (MRI in utero at 22 weeks of gestation), the latest recognition was at 12 months of age. A voiding cystourethrography was performed in 4 patients to confirm the diagnosis. In 4 patients the bladder duplication could be classified according to Abrahamson with 3 complete reduplications and one complete sagittal septum.

All patients suffered from associated congenital diseases, but only one patient had urinary tract infections. Surgical treatment was only performed in one patient. Median follow-up was 34 months.

Urinary bladder duplications reflect extremely seldom disorders that are almost always associated with other congenital anomalies. Treatment depends on patients’ symptoms and associated conditions and hence needs to be individualized to each patient.