**Question:** Nesidioblastoma is due to hyperplasia of-

A. Beta cells
B. Alpha cells
C. Parafollicular cells
D. Dopaminergic neurons

**Core Concept:** Nesidioblastoma is a rare pancreatic neoplasm characterized by the overgrowth of insulin-secreting beta cells. It is considered a form of pancreatic neuroendocrine tumor (PNET) that can lead to hyperinsulinism, a condition characterized by excessive insulin production and hypoglycemia.

**Why the Correct Answer is Right:** Nesidioblastoma arises from the overgrowth of beta cells, which are responsible for producing and releasing insulin into the bloodstream. The hyperplasia of these cells results in the excessive production of insulin, causing hypoglycemia and other symptoms related to hyperinsulinism.

**Why Each Wrong Option is Incorrect:**

A. Beta cells: Incorrect because the correct answer explains that nesidioblastoma is due to beta cell hyperplasia.
B. Alpha cells: These cells produce glucagon, which counteracts insulin and does not cause hyperinsulinism.
C. Parafollicular cells (C cells): These cells produce calcitonin and are not involved in insulin production or hyperinsulinism.
D. Dopaminergic neurons: These neurons are not related to insulin production or hyperinsulinism, which is primarily caused by beta cell hyperplasia.

**Clinical Pearl:** Nesidioblastoma is a rare and potentially life-threatening condition requiring prompt diagnosis and management. Hypoglycemia is the hallmark symptom, and early intervention is crucial to prevent severe complications and improve patient outcomes.