Purpose/Background: Small intestine neuroendocrine tumors (SI-NETs) are a common small bowel malignancy arising from enterochromaffin cells within the intestinal mucosa.[1] They produce serotonin and other vasoactive substances. [1-2] In early stages, symptoms are vague and can include diarrhea and abdominal pain. Due to their indolent nature and broad symptoms, diagnosis is frequently delayed. [3] We present a case in which SI-NETs were unexpectedly discovered during surgery for intestinal ischemia, highlighting how unexplained diarrhea can be the only sign of an otherwise silent cancer.
Methods/Interventions: -
Results/Outcomes: We report a case of an 82-year-old woman with a medical history of chronic myeloid leukemia and chronic gastritis who presents with worsening abdominal pain. Patient had a 5-month history of diarrhea with extensive outpatient work-up including stool studies, non-contrast computed tomography (CT) scan, CT enterography, and colonoscopy which were all unrevealing. On admission, examination showed a soft but diffusely tender abdomen. Laboratory results showed leukocytosis without lactic acidosis. CT scan demonstrated distended distal ileal loops with wall thickening, fat stranding, and mesenteric lymphadenopathy concerning for inflammatory or infectious enteritis. She was started on broad-spectrum antibiotics. CT Angiography revealed no pneumatosis or mesenteric occlusion but showed ileal thickening and mesenteric lymphadenopathy.
Given worsening pain in the right lower quadrant, she underwent diagnostic laparoscopy which revealed ischemic small bowel and right colon. She underwent an exploratory laparotomy with small bowel resection (75 cm), right hemicolectomy, and temporary abdominal closure. At re-exploration, an additional 20 cm of ischemic small bowel was resected, followed by primary anastomosis and abdominal closure.
Pathology revealed four well-differentiated SI-NETs with 2/9 mesenteric lymph nodes positive for metastasis. Immunohistochemistry was positive for chromogranin A and CD56. She was initiated on octreotide, continued outpatient octreotide monthly, and had marked improvement in her chronic diarrhea.
Conclusion/Discussion: SI-NETs are notorious for their subtlety. Despite extensive outpatient evaluation the SI-NETs escaped detection. This patient’s improvement on somatostatin analog therapy illustrates both diagnostic confirmation and functional control of hormone-mediated diarrhea. Our patient suffered for months with unexplained diarrhea whose diagnosis only revealed itself due to an ischemic bowel. The coincidence of bowel ischemia and SI-NETs calls for a deeper look at the underlying physiology.
SI-NETs can cause of bowel ischemia through the release of tachykinins, histamines and other bioactive amines which cause mesenteric fibrosis and vasoconstriction contributing to mucosal hypoperfusion and ischemia. [4] In this case, what appeared to be a vascular compromise may have been hormonally driven. [5]
SI-NETs may masquerade as chronic diarrhea and remain undiagnosed until incidentally discovered during surgery for other complications. This case emphasizes the need for attentiveness in evaluating chronic diarrhea of unknown etiology and demonstrates how SI-NETs should be a part of the differential. Early detection can potentially prevent complications like bowel ischemia and improve patient’s quality of life. [4-6]
