Urachal Cyst

A urachal cyst is a small fluid-filled sac that forms in the lower belly area, specifically between the belly button and the bladder. It happens when a tube called the urachus, which connects the bladder to the umbilical cord before birth, does not close properly. This condition affects the urinary system and can cause discomfort or infection if the cyst becomes swollen or filled with bacteria. People with a urachal cyst might notice a lump or pain near the belly button, and sometimes fluid can drain from the area. Although it is often present from birth, symptoms may not appear until later in life. The cyst can sometimes lead to complications like infection or, rarely, cancer. Understanding this condition helps explain unusual belly symptoms related to the bladder area.

Urachal cyst is a congenital anomaly resulting from incomplete obliteration of the urachus, a fetal remnant connecting the bladder dome to the umbilicus. Normally, the urachus involutes to form the median umbilical ligament, but failure of this process leads to cyst formation along the urachal tract. The cyst is typically located in the midline between the bladder and umbilicus and is lined by urothelium or glandular epithelium. Clinically, it may remain asymptomatic or present with symptoms due to infection, inflammation, or mass effect. Complications include recurrent urinary tract infections, abscess formation, and rarely malignant transformation into adenocarcinoma. Diagnosis and management are important to prevent these sequelae and to distinguish it from other midline abdominal masses.