Endocrine Neoplasms
posted in The Aging Liver |Kndocrine tumors arise from the neuroendocrine cells of the pancreas predominantly in the islets of Ihe pancreatic body and tail. However, enterochromaffin cells and other neuroendocrine cells can arise anywhere in Ihe GI tract. Endocrine tumors are rare in older persons.
These tumors are indistinguishable microscopically without special immunochemical staining. Localization of tumors can be aided by CT scan, portal venous sampling, and intraoperative ultrasonography. They may be cither nonfunctioning or functioning (ie, hormone secreting).
Nonfunctioning tumors may cause obstruction of the biliary tract or duodenum, bleeding into the GI tract, or an abdominal mass. Functioning lumors produce various syndromes.
Insulinomas, which may be single or multiple, produce insulin and arc identified by episodes of hypoglycemia, which may progress to coma in severe cases. Insulinomas are rarely malignant. Removal of all tumor tissue results in complete cure.
Gastrinomas produce the Zollinger-RIHson syndrome, an extremely virulent ulcer diathesis with excessive gastric acid secretion and diarrhea. The lumors can occur near the ampulla of Vater or the antrum as well as in the pancreas and are malignant in about 90% of cases. If metastasis does not occur, complete excision of Ihe lumor is curative. If metastasis does occur, various therapeutic modalities may be used, including administration of large doses of Hb-receptor blockers or omeprazole and, if medical therapy fails, gastric surgery to reduce acid secretion.
Glucagonomas secrete glucagon and have a high potential for malignancy. They lead to mild diabetes mellilus and a severe dermatitis involving portions of the lower half of the body. Although complete removal may not be possible, debtilking the tumor may help relieve symptoms. Streplozocin can help treat Ihe residual (umor.
Vipomas produce vasoactive intestinal polypeptide, pancreatic polypeptide, and perhaps other hormones. Recause the primary characteristics are watery diarrhea, hypokalemia, and achlorhydria, the disease is also known as the WDHA syndrome. Half of the tumors are malignant. As much tumor as possible should be resected, and the residual tumor should be treated with streplozocin.
Somatostatinomas are rare tumors that secrete somaloslatin. Clinical findings include diabetes, steatorrhea, and achlorhydria.
These clinical conditions can sometimes present as multiple endocrine neoplasia syndromes, in which tumors or hyperplasia occurs in two or more endocrine glands. Usually, these conditions are associated with tumors or hyperplasia of the parathyroid, pituitary, thyroid, or adrenal glands.
