Among patients presenting with Zollinger-Ellison syndrome, 20 to 60% have MEN 1. A severe secretory diarrhea can develop and cause fluid and electrolyte depletion with non–β-cell tumors. This complex, referred to as the watery diarrhea, hypokalemia and achlorhydria syndrome (VIPoma) has been ascribed to vasoactive intestinal polypeptide, although other intestinal hormones or secretagogues (including prostaglandins) may contribute. Hypersecretion of glucagon, somatostatin, chromogranin, or calcitonin, ectopic secretion of ACTH resulting in Cushings syndrome, and hypersecretion of somatotropin–releasing hormone (causing acromegaly) sometimes occur in non–β-cell tumors. All of these are rare in MEN 1.Nonfunctioning pancreatic tumors also occur in patients with MEN 1 and may be the most common type of pancreatoduodenal tumor in MEN 1. The size of the nonfunctioning tumor correlates with risk of metastasis and death. Pituitary
Pituitary tumors occur in 15 to 42% of MEN 1 patients. From 25 to 90% are prolactinomas. About 25% of pituitary tumors secrete growth hormone or growth hormone and prolactin. Excess prolactin may cause galactorrhea, and excess growth hormone causes acromegaly clinically indistinguishable from sporadically occurring acromegaly. About 3% of tumors secrete ACTH, producing Cushings disease. Most of the remainder are nonfunctional. Local tumor expansion may cause visual disturbance, headache, and hypopituitarism. Pituitary tumors in MEN 1 patients appear to be larger and behave more aggressively than sporadic pituitary tumors. Other manifestations
Adenomas of adrenal glands occurs occasionally in MEN 1 patients. Hormone secretion is rarely altered as a result, and the significance of these abnormalities is uncertain.
Tumors that demonstrate neural differentiation by light microscopy, immunohistochemistry, or electron microscopy have been traditionally labeled PNETs, and those that are undifferentiated by these analyses have been diagnosed as Ewings sarcoma." PNET of the CNS
PNET of the CNS generally refer to supratentorial PNETs. In the past medulloblastomas were considered PNETs; however, they are genetically, transcriptionally and clinically distinct. As such, "infratentorial" PNETs are now referred to as medulloblastoma. Pineoblastomas are embryonal tumours originating in the pineal gland and are likely distinct from supratentorial PNETs. Treatment
The approach to management of a CNS PNET is first to obtain detailed imaging through MRI, as well as additional scans of the patients body (X-ray, CT, PET, even bone marrow biopsies) to look for metastasis or other associated malignancies. The tumor will then need to be biopsied to confirm the diagnosis. After the diagnosis of a CNS PNET is confirmed, management includes neoadjuvant chemotherapy and radiation (to reduce tumor size burden), complete surgical resection with confirmed negative margins, and/or additional adjuvant post-surgical chemotherapy. CNS PNET is aggressive and must be managed as so. Palliative care services should also become involved in the patients care team when the diagnosis is made. See also
Medulloblastoma
Ependymoma
Ewing family of tumors


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