Neuroendocrine GEP-Tumors (GEP-NET)


pancreatic NET (50-75 %) with elevated secretion of somatostatin
original lit.:
Ganda et al 1977 (N Engl J Med), Larsson et al 1977 (Lancet), Krejs et al 1979 (N Engl J Med)
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Pathology - Pathophysiology


mostly solitary small to very large tumors (1 - 10 cm) located in the pancreatic head; extrapancreatic in duodenum, papilla, jejunum, thymus, lung, CNS; frequently malignant (~ 75 %)
mild diabetes mellitus: simultaneous inhibition of insulin and glucagon - sometimes complicated by hypoglycemia ("loss of glucagon action");
cholelithiasis: inhibition of gallbladder contractions and release of bile juice
steatorrhea: inhibition of gastric and pancreatic secretion: enzymes, bicarbonate, loss of nutritional lipids



Typical clinical syndrome

1. steatorrhea, diarrhea (80 - 95 %)
2. mild diabetes mellitus (50 - 95 %)
3. cholelithiasis (35 - 95 %)
other symptoms: hypochlorhydria, delayed gastric emptying, dyspepsia (vomiting), weight loss



Laboratory: hyperglycemia without ketonemia, elevated weight of stools, elevated stool fat loss (10-30 g)

hypersomatostatinemia (estimation of SLI difficult; SS-28, SS-14; normal in plasma : < 100 pg/ml): moderate (several 100 pg/ml) to excessive (>10.000 pg/ml)
important: somatostatin conc. in patients with diabetes (no family history) + unexplained steatorrhea + gall stones + incidental proof of a pancreatic or intestinal tumor

potential provocational test: i.v.-tolbutamide; i.v.-calcium-pentagastrin-stimulation

surgical resection - surgery of liver (metastases) - chemoperfusion and -embolisation - chemotherapy
symptoms: symptomatic therapy unavailable; somatostatin analogs ineffective upon SLI conc., adjuvant therapy of diabetes (insulin therapy difficult due to danger of hypoglycemia - suppression of glucagon), substitution of enzymes, nutritional alimentation