## **Core Concept**
The clinical presentation described for the newborn, including a bloated abdomen and decreased passage of meconium, is suggestive of **Hirschsprung's disease**. This condition is characterized by the congenital absence of ganglion cells in the distal bowel, leading to a functional obstruction. The diagnosis is often confirmed by a rectal biopsy.

## **Why the Correct Answer is Right**
The correct answer, which shows an absence of ganglion cells, is indicative of **Hirschsprung's disease**. In this condition, the affected segment of the bowel lacks ganglion cells, which are essential for the relaxation of the intestinal smooth muscle and the propulsion of intestinal contents. The absence of these cells leads to a persistent contraction of the affected segment, causing an obstruction. The full-thickness rectal biopsy is a diagnostic gold standard, as it allows for the assessment of the presence or absence of ganglion cells.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option might show normal ganglion cells, which would not support the diagnosis of Hirschsprung's disease in a patient with suggestive symptoms.
- **Option B:** This could represent another pathological condition affecting the rectum but does not specifically relate to the absence of ganglion cells seen in Hirschsprung's disease.
- **Option D:** Similarly, this option does not directly correlate with the diagnostic features of Hirschsprung's disease.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **Hirschsprung's disease** is often suspected in newborns with abdominal distension and failure to pass meconium within the first 48 hours of life. The definitive diagnosis is made by rectal biopsy showing an absence of ganglion cells. A useful mnemonic is "4-8-12": suspicion of Hirschsprung's should arise if there's abdominal distension, and no passage of meconium by 4 days, confirmed by biopsy around 8 days, with surgical intervention often planned around 12 days of life.

## **Correct Answer:** C. Absence of ganglion cells.