A large urachal cyst presenting with lower urinary tract symptoms and a falsely elevated post-void residual on bladder scan.

The urachus is an embryologic remnant that connects the bladder to the umbilicus and typically obliterates during gestation. Urachal cysts are one of the most common congenital urachal anomalies. Urachal cysts may be found incidentally on imaging or present as a palpable mass with abdominal pain and fever. We present a case of a young male with a urachal cyst who presented with lower urinary tract symptoms and a falsely elevated post void residual (PVR) volume on bladder scan. This case illustrates an atypical presentation of a large urachal cyst and highlights the limitations of bladder scanner post-void residual determination.