What is the characteristic abdominal mass found in pyloric stenosis?

In pyloric stenosis, the characteristic abdominal mass that is typically palpated during a physical examination is often described as an "olive-sized mass." This mass represents the hypertrophied pylorus, which is the muscle at the lower end of the stomach that becomes thickened, leading to the obstruction of food passage into the duodenum. The physical examination usually reveals this firm and smooth mass, which is distinctly felt in the right upper quadrant of the abdomen, just beneath the liver margin.

The description of the mass as "olive-sized" is fitting because it conveys both the shape and the approximate size of the pyloric muscle that is involved. This finding, along with clinical presentation—such as projectile non-bilious vomiting, dehydration, and sometimes weight loss in infants—helps establish the diagnosis of pyloric stenosis.

In contrast, the other options do not accurately represent the typical findings associated with pyloric stenosis. For instance, a fried egg mass does not relate to any established pediatric condition and does not describe a palpable structure. Similarly, a soft, tender mass or a tender, fluctuating mass would not be consistent with the consistent, firm nature of the pyloric muscle affected in this condition, which is generally not associated with tenderness