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A recommend surveillance program for Multiple Endocrine Neoplasia Type 1 has been suggested by the International Guidelines for Diagnosis and Therapy of MEN syndromes group.
Management of MEN2 patients includes thyroidectomy including cervical central and bilateral lymph nodes dissection for MTC, unilateral adrenalectomy for unilateral pheochromocytoma or bilateral adrenalectomy when both glands are involved and selective resection of pathologic parathyroid glands for primary hyperparathyroidism.
Familial genetic screening is recommended to identify at risk subjects who will develop the disease, permitting early management by performing prophylactic thyroidectomy, giving them the best chance of cure.
Prognosis of MEN2 is mainly related to the stage-dependant prognosis of MTC indicating the necessity of a complete thyroid surgery for index cases with MTC and the early thyroidectomy for screened at risk subjects.
Although not officially categorized as multiple endocrine neoplasia syndromes, Von Hippel-Lindau disease and Carney complex are two other autosomal dominant endocrine tumor syndromes with features that overlap the clinical features of the MEN syndromes. Although not transmitted in the germline, McCune-Albright syndrome is a genetic disorder characterized by endocrine neoplastic features involving endocrine glands that overlap with those involved in MEN1 or MEN2.
The table in the multiple endocrine neoplasia article lists the genes involved in the various MEN syndromes. Most cases of MEN2 derive from a variation in the "RET proto-oncogene", and are specific for cells of neural crest origin. A database of MEN" implicated RET mutations is maintained by the University of Utah Department of Physiology.
The protein produced by the "RET gene" plays an important role in the TGF-beta (transforming growth factor beta) signaling system. Because the TGF-beta system operates in nervous tissues throughout the body, variations in the RET gene can have effects in nervous tissues throughout the body.
MEN2 generally results from a gain-of-function variant of a "RET gene". Other diseases, such as Hirschsprung disease, result from loss-of-function variants. OMIM # lists the syndromes associated with the RET gene.
Neuroendocrine tumors (NETs) are neoplasms that arise from cells of the endocrine (hormonal) and nervous systems. Many are benign, while some are malignant. They most commonly occur in the intestine, where they are often called carcinoid tumors, but they are also found in the pancreas, lung and the rest of the body.
Although there are many kinds of NETs, they are treated as a group of tissue because the cells of these neoplasms share common features, such as looking similar, having special secretory granules, and often producing biogenic amines and polypeptide hormones.
Clinical trials of protein kinase inhibitors, which block the abnormal kinase proteins involved in the development and growth of medullary cancer cells, showed clear evidence of response in 10-30% of patients. In the majority of responders there has been less than a 30% decrease in tumor mass, yet the responses have been durable; responses have been stable for periods exceeding 3 years. The major side effects of this class of drug include hypertension, nausea, diarrhea, some cardiac electrical abnormalities, and thrombotic or bleeding episodes.
Vandetanib, trade name Caprelsa, was the first drug (April 2011) to be approved by US Food and Drug Administration (FDA) for treatment of late-stage (metastatic) medullary thyroid cancer in adult patients who are ineligible for surgery.
Cabozantinib, trade name Cometriq, was granted marketing approval (November 2012) by the U.S. FDA for this indication. Cabozantinib which is a potent inhibitor of RET, MET and VEGF was evaluated in a double-blind placebo controlled trial. It was shown to improve overall survival by 5 months for the treated cohort vs. placebo, which was not statistically significant. However, cabozantinib was particularly effective in patients with the RET M918T mutation, extending overall survival by roughly 2 years, doubling survival vs. untreated patient (4 years vs. 2 year). Treatment with cabozantinib did require many dose reduction to mitigate side effects. It has been suggested that the trial dose of 140 mg was excessive, particularly in lower body mass patients. Ongoing trials have been scheduled to identify more optimal dosing regimes. Activity has been observed, in practice at doeses of 1.2 mg/kg.
Although estimates vary, the annual incidence of clinically significant neuroendocrine tumors is approximately 2.5–5 per 100,000; two thirds are carcinoid tumors and one third are other NETs.
The prevalence has been estimated as 35 per 100,000, and may be considerably higher if clinically silent tumors are included. An autopsy study of the pancreas in people who died from unrelated causes discovered a remarkably high incidence of tiny asymptomatic NETs. Routine microscopic study of three random sections of the pancreas found NETs in 1.6%, and multiple sections identified NETs in 10%. As diagnostic imaging increases in sensitivity, such as endoscopic ultrasonography, very small, clinically insignificant NETs may be coincidentally discovered; being unrelated to symptoms, such neoplasms may not require surgical excision.
Surgery and radiation therapy have been the major treatments for medullary thyroid carcinoma.
Treatment of Hirschsprung's disease consists of surgical removal (resection) of the abnormal section of the colon, followed by reanastomosis.
The Swedish-American surgeon, Orvar Swenson (1909–2012), who discovered the cause of Hirschsprung’s, first performed its surgical treatment, the pull-through surgery, in 1948. The pull-through procedure repairs the colon by connecting the functioning portion of the bowel to the anus. The pull-through procedure is the typical method for treating Hirschsprung’s in younger patients. Swenson devised the original procedure, and the pull-through surgery has been modified many times.
Currently, several different surgical approaches are used, which include the Swenson, Soave, Duhamel, and Boley procedures. The Swenson procedure leaves a small portion of the diseased bowel. The Soave procedure, named after the Italian pediatric surgeon, Franco Soave (1917–1984), leaves the outer wall of the colon unaltered. The Boley procedure, pioneered by the American surgeon, Scott Boley (b. 1941), is a small modification of the Soave procedure, so the term "Soave-Boley" procedure is sometimes used. The Duhamel procedure, named for the French pediatric surgeon, Bernard Duhamel (1917–1996), uses a surgical stapler to connect the good and bad bowel.
For the 15% of children who do not obtain full bowel control, other treatments are available. Constipation may be remedied by laxatives or a high-fiber diet. In those patients, serious dehydration can play a major factor in their lifestyles. A lack of bowel control may be addressed by a stoma, similar to a colostomy. The Malone antegrade colonic enema (ACE) is also an option. In a Malone ACE, a tube goes through the abdominal wall to the appendix, or if available, to the colon. The bowel is then flushed daily. Children as young as 6 years of age may administer this daily flush on their own.
If the affected portion of the lower intestine is restricted to the lower portion of the rectum, other surgical procedures may be performed, such as a posterior rectal myectomy.
The prognosis is good in 70% of cases. Chronic postoperative constipation is present in 7 to 8% of the operated cases. Postoperative enterocolitis, a severe manifestation, is present in the 10–20% of operated patients.