**Core Concept**
Neuroblastoma is a type of pediatric cancer that arises from immature nerve tissue, most commonly in the adrenal glands or along the sympathetic nervous system. In neonates, it often presents as an abdominal mass due to its rapid growth.

**Why the Correct Answer is Right**
Neuroblastoma is the most common extracranial solid tumor in children, with a peak incidence between 5 and 10 years of age. However, it can also occur in neonates, often presenting as a palpable abdominal mass. The tumor arises from the neural crest cells, which migrate to various parts of the body during embryonic development. In the case of neuroblastoma, these cells accumulate in the adrenal glands or along the sympathetic nervous system, leading to tumor formation. The rapid growth of neuroblastoma can cause abdominal distension and a palpable mass in neonates.

**Why Each Wrong Option is Incorrect**
**Option A:** Wilms tumor is a different type of pediatric cancer that arises from the kidneys, not the adrenal glands or sympathetic nervous system. It is a common abdominal mass in children, but not as common as neuroblastoma in neonates.

**Option B:** Polycystic kidney disease is a genetic disorder characterized by the growth of numerous fluid-filled cysts in the kidneys. It is not a type of cancer and would not typically present as a palpable abdominal mass in neonates.

**Option D:** Rhabdomyosarcoma is a type of soft tissue sarcoma that arises from skeletal muscle. While it can occur in children, it is not as common as neuroblastoma in neonates and typically presents in a different location.

**Clinical Pearl / High-Yield Fact**
Neuroblastoma often secretes catecholamines, leading to symptoms such as hypertension, tachycardia, and flushing. This can be a clue to the diagnosis in neonates with an abdominal mass.

**✓ Correct Answer: C. Neuroblastoma**