Urachal Remnants: Sleeping lions or another downside of too much medical care?
On one hand, some doctors advocate removing all urachal remnants due to their potential to cause infections or degenerate into a bad type of cancer later in life (sleeping lion). Other doctors instead believe remnants are common and extremely unlikely to result in malignant degeneration –i.e, false alarms generated from ordering too many studies.
The discrepancy in between the 2 camps stems from the fact that they are both referring to different things.
Symptomatic or “ugly” remnants
The literature in favor of excision (here and here) consists of small series (under 50 cases) of symptomatic/”ugly” urachal remnants — causing pain, discharge, urine flow from the umbilicus, or a visible/infected mass. They postulate that without excision, recurrent infections will occur, and ultimately cancer due to chronic inflammation.
Itty bitty incidental remnants
This study in favor of observation found that, contrary to prior beliefs, urachal remnants are quite common. In my own practice, I find a few incidental urachal remnants every month. One of our radiologists told me they don’t always dictate in their report if they see a urachal remnant: they are so common that they consider them normal.
Surgery for some, observation for most
My take is that both viewpoints are right. If I see a large or symptomatic urachal remnant there is no question I would recommend excision. The 3 pictures below show a large, complex, and solid but asymptomatic remnant. Pathology found intestinal epithelium and mucus inside the cyst. I can see one of these degenerating into urachal carcinoma or eventually getting infected. Surgery also happens to be very safe with a very low complication rate.
That been said, most of the urachal remnants I see are asymptomatic and simple:
For the latter group, I agree with this Canadian study that considers excision unwarranted. The study estimated that close to 6,000 surgeries to remove urachal remnants would be needed to prevent one case of urachal adenocarcinoma. To put that into perspective, they compared this number to the number of prophylactic mastectomies needed to prevent one case of breast cancer: 8.
We don’t even know if these small urachal remnants can actually transform into tumors. Everyone you put a laparoscope on has a urachal remnant, so everyone has urachal tissue from which to develop a tumor. The assumption that only the ones that can be visible on ultrasound can transform into cancer is mostly unfounded.
I would not advocate for continued follow-up with ultrasounds since that would just make the family worry for no good reason: first, do no harm.
Urachal remnants are common incidental findings on ultrasound. Most should probably be left alone and forgot about, but a few might warrant excision.