A urachal cyst is a congenital birth defect where a small fluid-filled cavity remains between the umbilicus and the bladder. It is a remainder of the allantois, the structure used to remove waste during fetal development. In people with urachal cysts, part of the structure remains in place. Often, the patient will be asymptomatic until a problem develops, although sometimes, the cyst will be visible on an ultrasound exam of the abdomen conducted for other reasons.
Usually, a doctor diagnoses this condition in childhood. The patient may experience abdominal pain and tenderness, discharge around the umbilicus, and difficulty urinating. An ultrasound examination will reveal the fluid-filled cavity in a location where one should not be. Commonly, the urachal cyst contracts a bacterial infection, leading to swelling, pain, and irritation for the patient.
One potentially serious concern is the risk of rupture. As long as the cyst remains anchored in place, the patient should remain relatively stable, although infections can cause tissue death and complications like organ failure. If the structure breaks open, it can compress other organs and may potentially be fatal if internal bleeding occurs. In cases of rupture, the patient typically reports an acute onset of pain and discomfort, and may go into shock as a result of internal bleeding.
The typical treatment for a urachal cyst is surgery to address the abnormality. In patients with infections, the patient may need to remain on antibiotics to stabilize before the surgery can take place. In cases where neighboring tissue dies as a result of the infection, the surgery will include debridement to take this tissue out so it does not cause problems for the patient. The surgeon may be able to work laparoscopically, through a series of small incisions, so scarring will be minimal.
The reasons for cyst formation remain obscure. There do not appear to be any steps people can take during pregnancy to prevent cysts from growing, and they often appear independent of other fetal abnormalities. In cases where a baby has structural anomalies in the urinary tract, the doctor will conduct an ultrasound to check for problems like urachal cysts and kidney malformations, to rule out any associated complications. A pediatric urologist often takes charge of care for this condition, providing parents with advice and information on how to proceed. If the condition is not diagnosed until adulthood, the patient can see a regular urologist to discuss treatment options.