**Core Concept**
Werner's syndrome, also known as multiple endocrine neoplasia type 1 (MEN1), is a rare genetic disorder characterized by the occurrence of tumors in multiple endocrine glands. This condition is caused by mutations in the MEN1 gene, which encodes a tumor suppressor protein involved in the regulation of cell growth and differentiation.

**Why the Correct Answer is Right**
Phaeochromocytomas are typically associated with von Hippel-Lindau syndrome (VHL) or multiple endocrine neoplasia type 2 (MEN2), not MEN1. In MEN1, the most common endocrine tumors are those of the parathyroid glands (hyperparathyroidism), the pituitary gland (prolactinomas, somatotrophinomas, or other types), and the pancreas (gastrinomas, insulinomas, or other types). The pathogenesis of MEN1 involves the inactivation of the MEN1 gene, leading to the loss of tumor suppressor function and the development of endocrine tumors.

**Why Each Wrong Option is Incorrect**
**Option A:** Tumors of the anterior pituitary are a characteristic feature of MEN1, particularly prolactinomas and somatotrophinomas.
**Option B:** Tumors of the parathyroids, leading to hyperparathyroidism, are a hallmark of MEN1.
**Option C:** Pancreatic adenomas, particularly gastrinomas and insulinomas, are commonly found in patients with MEN1.
**Option D:** Phaeochromocytomas are not typically associated with MEN1, making this option the correct answer.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that MEN1 is a distinct clinical entity from MEN2, which is characterized by medullary thyroid carcinoma, pheochromocytomas, and hyperparathyroidism. The presence of pheochromocytomas should prompt a diagnosis of MEN2 rather than MEN1.

✓ Correct Answer: D. Phaeochromocytoma