Overview.
The syndrome is characterized by a combination of parathyroid, pancreatic islet cell, and pituitary tumors that have been found to cause the MEN-1 gene on chromosome 11, the Menin gene.The signs and symptoms of MEN-1 depend on the type of tumor that involves the patient. Clinical manifestations of hyperparathyroidism, pancreatic neuroendocrine tumors, and pituitary tumors may be seen.
Etiology
The disease tends to run in families.
Symptoms
The signs and symptoms of MEN-1 depend on the type of tumor involved in the patient. There can be hyperparathyroidism, pancreatic neuroendocrine tumors and pituitary tumors. Hyperparathyroidism is the most common and earliest presenting lesion in MEN-1, and may present with bone pain, pathologic fractures, elevated blood calcium, and urinary stones. Pancreatic neuroendocrine tumors include: gastrinomas, which are mostly malignant and prone to lymph node and liver metastases. Insulinoma, often multifocal and mostly benign, patients have hypoglycemic episodes. The rest are glucagon tumors, schwannomas and anaplastic tumors. Pituitary tumors:These include prolactinomas, growth hormone tumors, non-functioning tumors and ACTH tumors. In addition, MEN-1 can have other lesions: including adrenal non-functioning cortical tumors, carcinoid tumors (located in the pancreas, duodenum, thymus, and bronchi), thyroid adenomas, and subcutaneous lipomas.
Tests
1. Genetic test
2. Measurement of serum calcium, parathyroid hormone, gastrin, blood glucose, insulin and anterior pituitary hormone;
3. CT or MRI examination of pancreas, parathyroid gland and pituitary gland.
Diagnosis
Diagnosis is based on clinical manifestations, genetic history, and typical examination findings.
Treatment
Parathyroid and pituitary tumors are mainly treated surgically. Islet cell tumors are more difficult to manage because the lesions are small and difficult to detect, and multiple lesions are common. Diazoxide may be used as an adjunct in the management of hypoglycemia.
Treatment of gastrinomas is complex. Locate and resect the tumor in all patients if possible. If this is not possible, oxytocin is used, and proton pump blockers often achieve relief of peptic ulcer symptoms.H2 blockers are also available but are less effective.