What causes the antral nipple sign on abdominal ultrasound?
Let me know in the comments.
Click to reveal the answer
Answer:
The antral nipple sign is a nipple-like protrusion of redundant, hypertrophied pyloric mucosa prolapsing back into the gastric antrum, seen on infant ultrasound. It was described by Hernanz-Schulman and colleagues in 1995 in hypertrophic pyloric stenosis and validated by endoscopic correlation, which confirmed that the sonographic protrusion corresponds to genuine mucosal redundancy within the pyloric channel rather than to an artefact of scanning plane. It is one of several sonographic features of the condition and is used alongside the primary quantitative criteria of muscle wall thickness (3 mm or more) and pyloric channel length (15-17 mm or more). It must be distinguished from the target sign, the cross-sectional appearance of hypoechoic hypertrophied muscle surrounding echogenic mucosa, and from the cervix sign, the longitudinal indentation of the elongated narrowed channel into the fluid-filled antrum. It is a sonographic finding and should not be confused with the barium-era antral pad sign.
Why is it called so?
The redundant mucosa protrudes into the antral lumen as a rounded projection resembling a nipple.
Pathophysiology
In hypertrophic pyloric stenosis the circular muscle of the pylorus hypertrophies and the channel elongates and narrows. The mucosa lining that channel is not similarly constrained, so it becomes relatively redundant and is progressively crowded within the shortened luminal space. Gastric contractions against the obstructed outlet push this excess mucosa retrogradely, so it prolapses back through the proximal pyloric channel into the antrum and is imaged as a discrete nipple-shaped projection surrounded by fluid.
Alternative names: None
Other associated named signs: Target sign, cervix sign, double track sign, shoulder sign and the caterpillar sign of vigorous gastric peristalsis
References
Access all radiology signs posted so far: https://radiogyan.com/radiology-signs/
Improve Content And Help Your Colleagues!
Found an error in the post? Please let us know using our contact page and we will update it with due credits!
If you wish to contribute radiological images for this case (or any other article on the website), you can submit them here and you will be duly credited: Submit radiology case