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Neuroendocrine tumor of the ileum

Monday 06 April 2009, Igor Páv, M. D. and Branislav Kunčak, M. D.

The case of a patient with relapsing postprandial abdominal cramps.

69-years-old female presented with relapsing postprandial abdominal cramps. Laboratory tests showed mild anemia and hypalbuminemia. EGD and colonoscopy were negative. CT finding of thickened wall of short ileal segment with regional lymphadenopathy was suggestive of small intestinal tumor. Capsule endoscopy was performed and stenosing tumor of the ileum was found (Fig 1-3, Video 1). Because of positive results of 5-HIAA in urine and abnormal plasma chromogranin levels a neuroendocrine tumor (NET) was suspected.

The diagnosis was confirmed at surgery and the tumor was resected successfully.

Histology confirmed the diagnosis of neuroendocrine tumor (well differentiated endocrine carcinoma- low-grade malignancy NET) with mesenterial lymph nodes metastases and metastases to the omentum (Chapter Histology findings/Small intestine/Neuroendocrine tumor of the ileum Fig 1,2).


Neuroendocrine tumors (NET)

  • are tumors that are grouped together because of similarities in cell structure
  • arise from amine precursor uptake and decarboxylation (APUD) cells
  • rare tumors
  • can be found anywhere in body (GI tract, bronchus, lung, thyroid)
  • the majority occuring in GI tract (mainly in small intestine)
  • carcinoid is the most common type of NET
  • can be sporadic or as a result of genetic predisposition
  • functionally active NETs produce bioactive amines and/or hormnes and present with respective symptoms (carcinoid syndrome, Zollinger-Ellison syndrome, ..)
  • functionally inactive NETs: a) are diagnosed by chance; b) present as a pancreatic mass causing biliary obstruction; c) present with abdominal cramps due to intermitent intestinal obstruction; d) present with GI bleeding
  • according to WHO they can be classified into two main groups: 1.) well-differentiated neuroendocrine tumors; 2) poorly differentiated small-cell neuroendocrine carcinoma
  • most NETs are malignant (except for insulinomas, which are benign in more than 90% of cases)
  • well-differentiated NETs can be benign or malignant
  • malignancy is obvious when metastases are present
  • in the absence of metastases, malignancy is suggested by the presence of the following: tumor size more than 2cm, submucosal invasion, angioinvasion, invasion into perineural spaces, the presence of necroses and overt cell atypia, large number of mitoses, loss of chromogranin A immunoreactivity

Diagnosis of NETs

  • biochemical markers:
  1. plasma levels of hormones- insuline, gastrin, ..
  2. plasma level of chromogranin A (elevated also in functionally inactive tumors)
  3. urine 5-HIAA and others
  • imaging:
  1. somatostatin receptor scintigraphy (SRS)
  2. endoscopic ultrasonography (EUS)
  3. CT, MRI
  4. endoscopy (EGD, colonoscopy, capsule endoscopy, bronchoscopy, ..)
  • histology: immunohistochemical markers of NETs (neuron-specific enolase, synaptophysin, chromogranin A, ..)

Treatment of NETs

  • curative surgical removal (when possible)
  • control of hormon-mediated symptoms and tumor growth:
  1. somatostatine analogues
  2. interferon
  3. chemotherapy
  4. radiotherapy


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Fig. 1

Tumorous stenosis of the ileum (capsule endoscopy finding).

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Fig. 2

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Fig. 3

Video 1

Keywords: neuroendocrine tumor of the ileum, neuroendocrine tumor of the small intestine, NET, well differentiated endocrine carcinoma, low-grade malignancy NET, diagnosis and management of neuroendocrine tumors, capsule endoscopy, CT enterography, immunohistochemical markers of NETs, chromagranin A, 5-HIAA