Which of the following are the extraintestinal manifestations of Sipple syndrome?
**Core Concept**
Sipple syndrome, also known as Multiple Endocrine Neoplasia type 2A (MEN2A), is a rare genetic disorder characterized by the presence of medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. It is caused by mutations in the RET proto-oncogene. Extraintestinal manifestations of Sipple syndrome refer to the non-intestinal symptoms and complications associated with this condition.
**Why the Correct Answer is Right**
The extraintestinal manifestations of Sipple syndrome include pheochromocytoma, which is a type of adrenal gland tumor that secretes excess catecholamines, leading to hypertension, tachycardia, and other cardiovascular symptoms. Hyperparathyroidism is another manifestation, where one or more parathyroid glands become overactive, leading to elevated calcium levels in the blood. These manifestations are a result of the abnormal function of the RET proto-oncogene, which regulates the development and function of various endocrine glands.
**Why Each Wrong Option is Incorrect**
**Option A:** Medullary thyroid carcinoma is an intestinal manifestation of Sipple syndrome, not an extraintestinal one.
**Option B:** Hirschsprung disease is a congenital condition that affects the large intestine and is not associated with Sipple syndrome.
**Option C:** Pancreatic neuroendocrine tumors are not a characteristic feature of Sipple syndrome.
**Option D:** This option is incomplete and cannot be evaluated.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that Sipple syndrome is a hereditary condition, and family members of patients with this condition should be screened for the RET proto-oncogene mutation to prevent or diagnose the condition early.
**Correct Answer: C. Pancreatic neuroendocrine tumors are not a characteristic feature of Sipple syndrome.**