Multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type I (MEN1)is also, also known as Wermer syndrome, is an autosomal dominant genetic disease that results in proliferative lesions in multiple endocrine organs, particularly the pituitary gland, islet cells of the pancreas and parathyroid glands.

There are other multiple endocrine neoplasia syndromes and these are discussed separately. 

Clinical presentation

Primary hyperparathyroidism is one of the commonest presentationspresentation, followed by pancreatic islet cell tumour with associated hypersecretion syndromes; gastrinomas are most common and associate with Zollinger-Ellison syndrome⁷.

Pathology

The abnormality is related to a tumour suppressor gene located in chromosome 11q13. MEN type I is an autosomal dominant syndrome characterised by^1-7:

• pituitary adenomas:
  • prolactinoma (most common)
  • 30% of patients, most frequently prolactinomas
• islet cell tumours of the pancreas: 50% of patients, and a significant cause of mortality, most often gastrinomas followed
  • gastrinoma (most common) followed by glucagonoma
  • 50-80% of patients
  • a significant cause of mortality
• proliferative parathyroid gland lesions ⁷
  • parathyroid hyperplasia: with resulting  (most common)
    • hyperparathyroidism seen is seen in 80-95% of patients
  • parathyroid adenoma
  • parathyroid carcinoma (rare)

Handy mnemonics for recalling MEN type I: 

• PPP or PiParPanc

Associations

• lipomas
• angiofibromas
• adrenal cortical lesions
  • adrenal adenomas
  • adrenocortical hyperplasia
  • cortisol-secreting adenomas
  • adrenal carcinomas (rare)
• carcinoid tumours
• hepatic focal nodular hyperplasia ⁵
• Zollinger-Ellison syndrome ⁶

Treatment and prognosis

Pancreatic malignancy is the leading cause of mortality in MEN type I. 

History and etymology

ItMEN1 was first characterised by P Wermer et al. in 1954 ³.

See also

• MEN1 (Wermer syndrome)
• MEN2 (multiple endocrine adenomatosis)
  • MEN2a (Sipple syndrome)
  • MEN2b (mucosal neuroma syndrome)
  • familial medullary thyroid carcinoma
• MEN4
• Carney complex