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Key words:
neuroendocrine tumor, NETs, small bowel.
Background
Primary small bowel malignant tumors represent only the 1-2% of all gastrointestinal neoplasms. Neuroendocrine tumors (NET) are classified as a rare subgroup of malignant diseases, although they are the second most common malignant tumors of the small bowel after adenocarcinoma.[1, 2]
These tumors are asymptomatic for a long time, or occurs with gastrointestinal bleeding, carcinoid syndrome, abdominal pain or bowel obstruction, thus the diagnoses is often challenging.[3]
Case Report:
Our patient is a 46-year-old man admitted for abdominal pain and intestinal obstruction.
Diabetes and hypertension in his case history. The CT scan of the abdomen reveals a small bowel stenosis of about 4 cm in its proximal tract associated with intussusception, multiple liver and lymphnodes metastases. The radiologist suspected a neuroendocrine tumor of the ileum due to the typical hypervascularization of these metastases.
During surgery, multiple intestinal nodules were detected, and a small bowel resection was performed (67 cm length, Figure 1).
The pathology report showed multiple NET lesions (15 tumors, diameter between 15 and 4 mm, grade 1, Figure 2). Metastases were found in 11 of total 34 analyzed lymphnodes.
The patient underwent adjuvant oncological treatment.
Figure 1. View of the surgical specimen
Figure 2. Internal view of the small bowel showing multiple NETs
Discussion:
NETs of the small bowel commonly occur as a surgical emergency with symptoms of obstruction and
intussusception, as the present case.
Moreover, according to the international guidelines, surgical treatment is recommended in multiple intestinal NET lesions[4]. Multiple tumors are found in up to 40% of cases[5], and even small tumors under 1cm may show early lymphnode metastases.
NETs larger than 2cm have an increased risk of lymphnodes and liver metastases with a probability of 80% and 20% respectively[6]. The carcinoid syndrome, which occurs in 20-30% of patients with NETs, is often (95%) associated with the presence of liver metastases[4]. In our case, the CT scan allowed to suspect the type of disease through the typical metastases characteristics. The final diagnosis was only possible after the surgical exploration and subsequent pathological analysis.
In our patient the diameter of the lesions detected was between 1,5 and 0,4 cm, without carcinoid syndrome but with liver and lymphnode metastases. In cases with distant metastases, the decision of whether resect or not the primary tumor is based on the following considerations[4]:
- Achieving R0 resection including the primary tumor and distant metastases (curative intent).
- In patients with symptoms due to intestinal obstruction or bleeding, the palliative resection of the primary tumor is mandatory as life-saving treatment. Moreover, mesenteric pathological lymphnodes should be removed as completely as possible to avoid vessels occlusion with consequent intestinal ischemia.
- Non-curative primary tumor resection in metastatic disease seems to improve overall survival, and therefore may be considered. This evidence is shown in a recent systematic review of the literature that analyze data from six comparative observational studies[7]. Due to the limitations of the current literature more
The prognosis of patients with NETs depends on both disease staging and grading. Jann et al.[8] reported a 5-year tumor-specific survival rate for small bowel NETs of 100% for stage I and II, 97.1% for stage III and 84.8% for stage IV.
Main Article Content
Abstract
Neuroendocrine tumors of the small bowel are rare malignancies that often occur in the case of bowel obstruction or intestinal bleeding. The present case is a 46-year-old man who underwent emergency surgery for obstruction due to a rare presentation of multiple neuroendocrine lesions located in an intestinal loop. Pathology showed 15 NETs (grade 1) between 4 and 15 mm diameter with positive lymph nodes and liver metastases already detected by the preoperative CT scan.