Carcinoid of lung (bronchial adenoma) arise from
**Core Concept**
Carcinoid tumors of the lung, also known as bronchial adenomas, are a type of neuroendocrine tumor that arises from the neuroendocrine cells of the bronchial epithelium. These cells are part of the diffuse neuroendocrine system, which also includes the parafollicular cells of the thyroid gland and the enterochromaffin cells of the gastrointestinal tract.
**Why the Correct Answer is Right**
Carcinoid tumors of the lung typically arise from the Kulchitsky cells, which are the neuroendocrine cells of the bronchial epithelium. These cells contain neurosecretory granules and express markers such as chromogranin A and synaptophysin. The pathogenesis of carcinoid tumors is thought to involve mutations in the MEN1 gene, which encodes a tumor suppressor protein that regulates cell growth and division.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a valid choice, as the question is asking for a specific cell type or location.
**Option B:** This option is incorrect because carcinoid tumors of the lung do not arise from the parafollicular cells of the thyroid gland, which are a different type of neuroendocrine cell.
**Option C:** This option is incorrect because carcinoid tumors of the lung do not arise from the enterochromaffin cells of the gastrointestinal tract, which are also a different type of neuroendocrine cell.
**Clinical Pearl / High-Yield Fact**
Carcinoid tumors of the lung can produce a variety of biologically active substances, including serotonin, histamine, and prostaglandins, which can cause a range of symptoms including flushing, diarrhea, and wheezing.
**Correct Answer:** C. Kulchitsky cells.