I spend two days a week overseeing prenatal ultrasounds and doing consults. The majority of those scans are Level II anatomy scan at 18 weeks. This is the major scan where we look at all the parts of the fetus, both for structural anomalies, as well as for clues to genetic abnormalities. It is Stressful, perhaps even STRESSFUL, because this scan is a comprehensive physical exam of a non-compliant body INSIDE of another body and therefore, by definition,gives you limited information. So we mine our information for clues about things that may or may not be going on. And we live in fear of Missing Something Important.
Today, mid-morning, I'm reviewing a scan, and as always, after reviewing the tech's pictures, I scan through the fetus myself. Quickly, I see something in the fetal stomach. What is that? Is it just a weird angle? Nope, I scan back and forth and it's really there. It's...debris. A mass? In the fetal stomach? I don't think I've ever seen this before.
My brain starts to move fast. What am I missing? Is this an unbeknownst-to-me clue to some terrible genetic problem? Is it some variant of duodenal atresia, which happens more in Down's syndrome? Is it some weird gastric tumor? I don't think that even happens prenatally, right? I mean, adrenal tumors, sure, but this? Is it some weird sign of slow gastric emptying, and therefore a sign of something systemic like cystic fibrosis?
I look around again the fetus again: fingers, toes, heart, brain: anything weird? No. It all looks...normal.
I email the head of ultrasound. While typing, I call my partner who's at the main academic hospital. "Oh, yeah," she says. "See it all the time. Don't worry about it."
"Um. What is it?"
"Dunno. But I have asked about it, and it's no big deal. Not clinically significant. I'll find you a reference later. Don't worry about it."
When I get off the phone with her,there's already an email back from my ultrasound chair. "See it all the time," he writes. "Don't worry about it."
But what IS it? I type back.
He doesn't respond right away.
Later in the day, when I have time to hunt around a bit, I find this on UpToDate*
Gastric pseudo-mass — In the second and third trimesters, debris is commonly visualized in the fetal stomach as a pseudo-mass consisting of discrete echogenic areas 4 to 12 mm in diameter (image 1) . The pseudo-mass is thought to represent swallowed cells (red blood cells, meconium, fetal skin cells) that have aggregated due to relatively poor gastric peristaltic activity early in the second trimester [1,2]. Gastric pseudo-masses resolve over time and are not associated with adverse neonatal outcome.
And now it has a long medical name, and I feel MUCH better.** I'm going to stop worrying about it.
*An online clinical resource. Reference at the link.
**Although, yeah: kinda gross. That's ok! Gross is normal.