Intravesical urachal cyst masquerading as a bladder malignancy: a case report

BACKGROUND: Urinary bladder masses in children are extremely rare. Certain benign conditions (e.g., ureterocele) can mimic malignant bladder masses. In this report, we present a unique case of a urachal cyst masquerading as a bladder malignancy. Unlike the typical location of urachal cysts along the course of the urachal tract, the cyst in this case was unexpectedly situated within the urinary bladder, leading to diagnostic difficulties. CASE PRESENTATION: A 2-year-old Bahraini boy presented with hematuria and dysuria for 2 weeks. There was no history of fever, abdominal pain, or vomiting. Physical examination yielded normal findings. Urinalysis showed numerous red blood cells and revealed positive results for nitrites and leukocyte esterase. Abdominal ultrasound showed a well-defined soft tissue lesion with internal vascularity located at the apex of the urinary bladder. Subsequently, magnetic resonance imaging demonstrated a thick-walled cystic structure arising from the anterosuperior wall of the bladder and protruding into its lumen. The patient underwent complete excision of the bladder lesion for the presumed diagnosis of rhabdomyosarcoma. Histopathological examination showed a fluid-filled space lined by stratified squamous epithelium with areas of intestinal metaplasia, revealing an unexpected diagnosis of a urachal cyst. The patient was discharged with complete resolution of symptoms. CONCLUSIONS: Intravesical urachal cysts are a rare type of congenital urachal anomaly that may simulate a bladder malignancy, particularly if associated with infection. This case emphasizes the importance of considering urachal cysts in the differential diagnosis of bladder masses, especially in children, and specifically when the lesion is midline in the anterosuperior wall of the bladder.