**Question:** A child presented with projectile, forcible, non-bilious vomiting. The most likely diagnosis is:

A. Gastroesophageal reflux disease (GERD)
B. Acute gastroenteritis
C. Peptic ulcer disease
D. Gastric malignancy

**Correct Answer:** D. Gastric malignancy

**Core Concept:**
Non-bilious vomiting in children can present in various forms. Projectile vomiting refers to the vomitus being expelled forcefully from the mouth. Forcible vomiting indicates the strength of the vomit expulsion. Non-bilious vomiting means that the vomitus does not contain bile. Understanding these clinical features is crucial in narrowing down the differential diagnosis and guiding further investigation and management.

**Why the Correct Answer is Right:**
In this scenario, the key factors that point towards the correct diagnosis are:
1. Non-bilious vomiting: Vomit does not contain bile, which is typically present in bilious vomiting due to gastrointestinal obstruction or gastrointestinal bleeding.
2. Projectile vomiting: The vomitus is expelled forcefully from the mouth, indicating a potential mechanical obstruction or underlying disease process.
3. Forcible vomiting: The vomitus is expelled with considerable force, which may indicate a significant cause.

**Why Each Wrong Option is Incorrect:**
A. Gastroesophageal reflux disease (GERD) is typically associated with retching, post-prandial vomiting, and could be bilious.
B. Acute gastroenteritis is usually characterized by watery stools, abdominal pain, and may present bilious vomiting.
C. Peptic ulcer disease (PUD) is associated with post-prandial vomiting, pain, and might present bilious vomiting.
D. Gastric malignancy is often associated with non-bilious vomiting (bile is not present), projectile vomiting, and forcible vomiting due to mechanical obstruction caused by the tumor.

**Clinical Pearl:**
Non-bilious vomiting with projectile and forcible vomiting in children should raise suspicion for gastric malignancies such as gastric cancer. These clinical features are often seen due to mechanical obstruction caused by the tumor. Furthermore, it is essential to consider gastric malignancies in the differential diagnosis of non-bilious vomiting in children, as they can present with similar clinical features as seen in GERD or gastroenteritis. However, the presence of projectile vomiting and forcible vomiting in addition to non-bilious vomiting can tip the clinical suspicion towards gastric malignancies, prompting further diagnostic workup and possibly prompting earlier intervention.