Malignant Neoplasms of the Small Intestine Workup

Updated: Sep 26, 2019
  • Author: Ponnandai S Somasundar, MD, MPH, FACS; Chief Editor: N Joseph Espat, MD, MS, FACS  more...
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Workup

Laboratory Studies

The complete blood cell count (CBC) may show mild anemia related to chronic blood loss. Liver function tests may reveal hyperbilirubinemia, which may be related to biliary obstruction from periampullary tumors. [16] Elevated transaminase levels also may be found in the presence of liver metastases. Carcinoembryonic antigen levels may be elevated.

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Imaging Studies

Plain abdominal x-ray films may reveal partial or complete small-bowel obstruction. Upper GI series with small-bowel follow-through show abnormalities in 53-83% of patients with small-bowel cancer. Small-bowel enteroclysis studies are done with double contrast barium enema, which has a sensitivity of 95%. However, it is difficult to perform as it requires a long tube to be inserted in the small bowel to instill air and contrast.

Abdominal CT scan may elucidate the site and extent of local disease and the presence of liver metastases.

Cross-sectional imaging can, in many cases, detect small-bowel malignancies that are usually inaccessible to conventional endoscopy. Modern multidetector computed tomographies permit accurate diagnosis, complete pretreatment staging, and follow-up of these lesions. [17]

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Procedures

Upper GI endoscopy with small-bowel enteroscopy (push enteroscopy) may identify and allow biopsy of lesions in the duodenum and jejunum. Push enteroscopy is difficult to perform. The endoscopes are long and difficult to manipulate. The procedure takes a long time to perform. Colonoscopy with retrograde ileoscopy may be useful in identifying ileal tumors.

Video capsule endoscopy (VCE) should be the third diagnostic test performed after upper and lower endoscopic evaluation of suspected small bowel bleeding. [18] A capsule about the size of a large vitamin is swallowed. It contains a small video camera, batteries that last about 8 hours, and a radiofrequency transmitter. The camera takes about 50,000 pictures as it passes the GI system. The pictures are captured in a device like a cassette player, which is strapped to the waist.  In comparison to radiographic imaging techniques,

VCE is highly sensitive in the detection of occult arterial and venous bleeding, especially if done during bleeding episodes. Its sensitivity is higher than CT angiography or magnetic resonance enteroclysis. [19]  VCE is useful as a screening tool in patients with suspected small bowel bleeding, but has a false-negative rate of up to 19% for neoplasms. Double-balloon enteroscopy (DBE) should still be performed in patients with a high clinical suspicion of small intestine lesion, following a negative VCE result. [18]

DBE allows deeper intubation of the small intestine compared with tradtional endoscopes. To perform DBE, the enteroscope and overtube are introduced into the small bowel, typically past the ampulla, and the balloon on the overtube is inflated. The enteroscope is then further advanced into the small bowel. The balloon on the DBE enteroscope is then inflated. The overtube is subsequently advanced over the enteroscope. Now both overtube and enteroscope are drawn back (with both balloons inflated on DBE), which allows the small bowel to plicate over the enteroscope. By repeating this series of steps, a longer distance can be traversed than with conventional endoscopy. Owing to deeper intubation of the small bowel and a higher success rate with the oral approach, this is the preferred route for lesions suspected to lie within the proximal 75% of the small bowel, whereas the rectal route is used for more distal lesions. [18]

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Histologic Findings

Adenocarcinoma are often moderately well differentiate and mucin producing with scattered endocrine cells. Mucin staining varies based on site of the lesion [20] :

  • Duodenum: positive for MUC1; negative for CK20
  • Jujunum and ileum: positive for CK20; negative for MUC1
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Staging

Small-bowel cancer is staged according to the American Joint Committee on Cancer tumor-node-metastasis (TNM) system. [2]

Primary tumor (T) is classified as follows:

  • TX: Primary tumor cannot be assessed.
  • T0: No evidence of primary tumor is present.
  • Tis: Carcinoma in situ is present.
  • T1: Tumor invades the lamina propria or submucosa.
  • T2: Tumor invades the muscularis propria.
  • T3: Tumor invades through the muscularis propria into subserosa or into nonperitonealized perimuscular tissue (mesentery or retroperitoneum), with extension of less than 2 cm.
  • T4: Tumor penetrates the visceral peritoneum or directly invades other organs or structures.

Regional lymph nodes (N) are classified as follows:

  • NX: Regional lymph nodes cannot be assessed.
  • N0: No regional lymph node metastasis is present.
  • N1: Regional lymph node metastasis has occurred.

Distant metastasis (M) is classified as follows:

  • MX: Presence of distant metastasis cannot be assessed.
  • M0: No distant metastasis is present.
  • M1: Distant metastasis has occurred.

Stage grouping is as follows:

  • Stage 0 - Tis, N0, M0
  • Stage I - T1-2, N0, M0
  • Stage IIA - T3, N0, M0
  • Stage IIB - T4, N0, M0
  • Stage IIIA - Any T, N1, M0
  • Stage IIIB - Any T, N2, M0
  • Stage IV - Any T, any N, M1

The staging for the duodenal polyps found in familial adenomatous polyposis is that of Spigelman. [21]

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