A 22-year-old student is scheduled to undergo parathyroidectomy for hyperparathyroidism associated with familial multiglandular syndrome. His sister developed peptic ulcer disease secondary to a Zollinger-Ellison (hypergastrinemia) 22 tumor of the pancreas. On examination, a swelling was noted over the posterior aspect of the patient’s fifth rib. What is the most likely finding?

**Core Concept**
Hyperparathyroidism associated with familial multiglandular syndrome is a genetic disorder characterized by the occurrence of multiple endocrine tumors, including parathyroid adenomas, pancreatic islet cell tumors, and other neoplasms. This condition is often associated with multiple endocrine neoplasia type 1 (MEN1) or multiple endocrine neoplasia type 2 (MEN2), which are inherited in an autosomal dominant pattern.

**Why the Correct Answer is Right**
The patient's clinical presentation, including the family history of peptic ulcer disease due to a Zollinger-Ellison syndrome-like tumor, and the presence of a swelling over the posterior aspect of the fifth rib, is highly suggestive of a Pancreatic neuroendocrine tumor (PNET). PNETs are known to cause excessive secretion of gastrin, leading to Zollinger-Ellison syndrome, and can also produce other hormones, such as insulin, glucagon, or somatostatin. The swelling over the rib may indicate an ectopic pancreatic tissue (Pancreatic heterotopia) or a PNET itself.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not relate to the patient's clinical presentation or family history.
**Option B:** This option is incorrect as it is not a common feature of familial multiglandular syndrome or MEN1/MEN2.

**Clinical Pearl / High-Yield Fact**
Familial multiglandular syndrome, particularly MEN1, is often associated with a high risk of developing other endocrine tumors, including pituitary adenomas, adrenal cortical tumors, and thyroid carcinomas. It is essential to screen family members of affected patients for these conditions.

**Correct Answer:** C. Pancreatic neuroendocrine tumor (PNET)

✓ Correct Answer: B. Osteitis fibrosa cystica (brown tumor) and subperiosteal resorption of the phalanges