Kian Liang Goh

Gastrointesinal: An unusual cause of gastric outlet obstruction

A 78 year-old man with a long standing history of hypertension and diabetes mellitus, presented with progressive yellowish discoloration of sclera, abdominal pain with tea colored urine and pale stools for two weeks. He also had significant loss of appetite and body weight. Initial ultrasound of the hepatobiliary system showed grossly dilated common bile duct and intra-hepatic ducts with a large pancreatic mass. An urgent ERCP was performed and a plastic biliary stent (8 cm, 7F) was successfully inserted. Subsequent abdominal CT scan showed a large tumor mass measuring 4.8 cm in diameter in the region of the head of pancreas (Figure 1), as well as multiple liver lesions and cysts (Figure 2). Laboratory evaluation showed normal values of tumor markers and urinary 5-Hydroxyindole acetic acid, with a markedly elevated serum chromogranin A of 180 U/L (normal < 17.2 U/L). CT-guided biopsy of the hepatic lesions was performed (Figure 3). He was discharged but presented again ten days later with complaints of nausea, vomiting and early satiety. An urgent gastroscopy and CT abdomen showed a larger pancreatic mass than before, compressing the pylorus. A diagnosis of malignant duodenal stenosis was made and an uncovered duodenal metallic stent, 12 cm x 10F was placed (Figure 4a and 4b). What is the underlying diagnosis? The biopsy revealed clusters of tumor cells with positive immunohistochemical study for chromogranin A. The patient had an aggressive malignant pancreatic carcinoid. A conservative approach was agreed upon and octreotide, a somatostatin analogue, was started for a month and subsequently changed to longacting lanreotide injection (intramuscular) every 3 weeks. The pancreas is a rare location for the development of carcinoid syndrome. In contrast to the previous reviews of pancreatic carcinoids, our patient was asymptomatic of carcinoid symptoms and the tumor was at the head of pancreas. In addition, the tumor had an aggressive progression resulting in gastric outlet obstruction. As seen in our patient, up to 75% of patients with carcinoid tumors develop hepatic metastases regardless of the location of the primary tumor. Long-acting somatostatin analogues and slow release lanreotide therapy have been shown to be highly effective in reducing and controlling the symptoms of carcinoid syndrome, as well as reducing the tumor size. The use of metallic duodenal stent has been documented to be useful and effective in relieving symptoms of more than six months for patients with metastatic malignancy and indicated as a palliative management.