Pancreatic Tumors

Chapter 345 Pancreatic Tumors

Pancreatic tumors can be of either endocrine or nonendocrine origin. Tumors of endocrine origin include insulinomas and gastrinomas. These and other functioning tumors occur in the autosomal dominantly inherited multiple endocrine neoplasia type 1 (MEN-1). Hypoglycemia accompanied by higher than expected insulin levels or refractory gastric ulcers (Zollinger-Ellison syndrome) indicate the possibility of a pancreatic tumor (Chapter 337). Most gastrinomas arise outside of the pancreas. The treatment of choice is surgical removal. If the primary tumor cannot be found or if it has metastasized, cure might not be possible. Treatment with high dose of a proton pump inhibitor to inhibit gastric acid secretion is then indicated.

The watery diarrhea-hypokalemia-acidosis syndrome is usually produced by the secretion of vasoactive intestinal peptide (VIP) by a non–α-cell tumor (VIPoma) (see Table 333-7). VIP levels are often, but not always, increased in the serum. Treatment is surgical removal of the tumor. When this is not possible, symptoms may be controlled by the use of octreotide acetate (cyclic somatostatin, Sandostatin), a synthetic analog of somatostatin. Pancreatic tumors secreting a variety of hormones, including glucagon, somatostatin, and pancreatic polypeptide have also been described. The treatment is surgical resection when possible.

Pancreatoblastomas, pancreatic adenocarcinomas, cystadenomas, and rhabdomyosarcomas are rarely encountered. Pancreatoblastoma, a malignant embryonal tumor that secretes α-fetoprotein and can contain both endocrine and exocrine elements, is the most common pancreatic neoplasm in young children. Presurgical chemotherapy should be considered for lesions not primarily resectable. Resection can be curative; adjuvant chemotherapy has been used but its effectiveness is not established.

Carcinoma of the exocrine pancreas is a major problem in adults, accounting for 2% of diagnoses and 5% of deaths due to cancer. It is very rare in childhood. No definite causes are known. Several genetic syndromes including mutations in the PRSS1 and MEN-1 genes lead to an increased incidence of pancreatic cancer in adult life. The Frantz tumor is a papillary cystic tumor usually found in girls and young women. Typical presenting symptoms are abdominal pain, mass, or jaundice. The treatment of choice is total surgical removal.

Insulinomas and persistent hyperinsulinemic hypoglycemia of infancy produce symptomatic hypoglycemia most commonly caused by mutations in the ABCC8 gene. Massive subtotal or total pancreatectomy is the treatment of choice when medical treatment fails (Chapter 86). These children might then develop pancreatic insufficiency and diabetes as a complication of surgery.

Pancreatic lesions in von Hippel-Lindau disease are usually benign and cystic. Cystadenomas, familial adenocarcinomas, and islet cell tumors are less common. Metastases have been reported, but adjuvant therapy after surgical excision cannot yet be recommended. The diagnosis is suggested by CT scanning.

Prognosis is good for completely resected endocrine tumors but very poor for carcinomas, even with extensive surgery. Children who survive partial or complete pancreatectomy may have decreased pancreatic exocrine and endocrine reserve.

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