Virtual Hospital: Radiology Resident Case of the Week: Document Title

Radiology Resident Case of the Week

Carcinoid Tumor

November 7, 1996

Thomas D. Berg
Peer Review Status: Not reviewed

Clinical Sx:
Symptoms range from abdominal pain and bowel obstruction to the carcinoid syndrome (flushing, diarrhea, bronchoconstriction, cyanosis and tachycardia).

Etiology/Pathophysiology
Carcinoids arise from the enterochromaffin cells of the GI tract, bronchi, biliary tract, and pancreas. The tumors excrete serotonin and other hormonally active compounds which can lead to the carcinoid syndrome. Interestingly, the liver metabolizes serotonin so tumors in the small bowel and mesentery rarely cause the carcinoid syndrome. Carcinoid syndrome can therefore suggest the presence of metastasis to non- GI locations.

Pathology:
Arise from the Kulchitsky cells and demonstrate round to oval nuclei which are deeply chromatic with a fine stippling throughout. Tumor invades the submucosa and muscularis. In extra appendiceal sites it frequently penetrates the bowel wall.

Miscellaneous
Carcinoids are the most common primary neoplasms of the small intestine. They can be located anywhere in the GI tract, bronchi, biliary tract, and pancreas. 90% are GI in origin and 25% are located in the small bowel.

Imaging
Primary carcinoids are often not visualized on CT exam. Sometimes they appear as soft tissue masses associated with the bowel wall. More often you will see findings related to the desmoplastic response in the mesentery induced by the primary tumor. This response may manifest as kinking of adjacent bowel loops or a stellate radiating pattern of mesenteric neurovascular bundles. Liver mets are common at the time of CT diagnosis.

Flouroscopic studies may show a small mural nodule or intussusception if the tumor is large enough to obstruct the bowel. Angiography displays irregularity of medium sized mesenteric arteries within the tumor area. Sometimes a sunburst pattern arises from the tumor or kinking and compression of vessels are seen.

Image 1 Image2

DDX
Adenocarcinoma, carcinoid tumor, inflammatory bowel disease (for this case).

Key references
Freeny, Stevenson, et al., Alimentary Tract Radiology, pgs 632-634

Megibow, Balthazar, et al., CT of the Gastrointestinal Tract, 1986 CV mosby co.

Robbins, et al., Pathologic Basis of Disease, W. B. Saunders Co. 1992

ACR Code

Keywords:
Carcinoid

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