A 48-year-old man is evaluated for abdominal pain and diarrhea. The patient characterizes his stool as voluminous and foul smelling. He has no significant past medical history. The patient drinks 6 cans of beer daily. On examination, he has normal bowel sounds and mild epigastric tenderness. A 72-hour stool collection shows excessive excretion of fecal fat. A CT scan of the abdomen is shown in the image below. Involvement of which of the following structures is most likely causing this patient's symptoms?
Show Explanatory Sources
Show Explanatory Sources
This patient with excessive alcohol use, epigastric pain, and steatorrhea likely has chronic pancreatitis with exocrine insufficiency. Atrophy and fibrosis of pancreatic acinar cells result in failed secretion of adequate amounts of digestive enzymes (eg, lipase). Consequently, patients may develop fat malabsorption with greasy, malodorous stools that are difficult to flush. A 72-hour stool collection can confirm excessive excretion of fecal fat.
The head, neck, and body of the pancreas are retroperitoneal, whereas the tail is peritoneal. The head of the pancreas lies in the curve of the duodenum and overlies the L2 vertebra, with a portion extending behind the superior mesenteric vessels (uncinate process). The neck connects the head to the body and lies anterior to the portal vein and superior mesenteric vessels. The pancreas body overlies the L1 and L2 vertebrae and makes contact posteriorly with the aorta, left adrenal gland, left kidney, and renal vessels. The tail of the pancreas courses within the splenorenal ligament alongside the splenic vessels.
(Choice A) This structure is the second (descending) part of the duodenum.
(Choice C) This structure is the inferior vena cava, which lies on the right side of the vertebrae in a retroperitoneal position.
(Choice D) This structure is the abdominal aorta, which lies on the left side of the vertebrae in a retroperitoneal position.
(Choice E) At this level in the abdominal cavity, these loops of small bowel represent jejunum. If this CT slice were lower in the abdomen, these loops would more likely represent ileum.
Educational objective:
Chronic pancreatitis often presents with epigastric pain and pancreatic exocrine insufficiency resulting in fat malabsorption/steatorrhea. On abdominal CT scan, the pancreas can be identified by its head in close association with the second part of the duodenum; its body overlying the aorta, left kidney, and renal vessels; and its tail lying within the splenorenal ligament.