A 56-year-old male presented with acute crampy, diffuse abdominal pain, distension, constipation and nausea. Last year, he had similar episode that was clinically diagnosed as diverticulitis and managed conservatively. Other review of systems was negative. Vitals signs were normal. Abdominal exam was remarkable for distension and left lower quadrant tenderness with no rebound tenderness, guarding or rigidity. Bowel sounds were hypoactive. All biochemical investigations were normal. CT scan of the abdomen showed partial small bowel obstruction in mid-ileum, conglomerated mesenteric lymph nodes and multiple hypodense liver lesions. Conservative management with bowel rest, hydration, and decompression with nasogastric tube was started. MRI of abdomen confirmed multiple ill-defined hyper vascular liver lesions suspicious for metastases. Given the small bowel findings, metastatic carcinoid tumor was suspected. Upon further questioning, the patient reported having intermittent night sweats, diarrhea and flushing after certain foods. Serum Chromagranin A, serotonin and urine 24 hour 5-HIAA levels were significantly elevated. PSA, CA 19-9 and AFP were normal. Pathology from liver biopsy showed low grade/ well differentiated neuroendocrine tumor. Immunohistochemical stain was positive for CDX2 and negative for TTF1 raising the possibility of a GI tract tumor. His clinical condition improved and he was discharged to follow up with medical and surgical oncology. An outpatient octreotide scan showed abnormal multifocal uptake consistent with metastatic carcinoid. No surgical intervention was recommended unless he started having recurrent bowel obstructions. A Somatostatin analogue, Lanreotide was started however he due to progression of the disease Everolimus was added.
Discussion:
Ileal carcinoid tumors are low grade, slow growing and well-differentiated neuroendocrine tumors arising from the midgut. Small intestine carcinoid represents about 0.25% of all newly diagnosed cancers in U.S. with majority of them located in the ileum. About 1/5thof them metastasize to regional mesenteric and para-aortic lymph nodes, and the liver. Carcinoid syndrome occurs when a “functioning tumor” secretes a variety of hormones and vasoactive substances causing flushing, diarrhea, asthma, telangiectasia etc. “Non-functioning” carcinoid tumors can cause partial small bowel obstruction due to bulk effect and local reaction. As in our patient, symptoms of bowel obstruction are intermittent and vague due to which patients are often misdiagnosed with irritable bowel syndrome or other gastrointestinal illnesses. The disease is often silent until it is locally advanced or distant metastases develop. Despite the nature, prognosis is surprisingly unfavorable as these cases mainly present at an advanced stage. Estimated 5-year survival rate is 65% in localized disease and 36% in metastatic disease.
Conclusions: As noted in our case, early diagnosis of carcinoid tumor favors a better prognosis. Hence, it is very important to obtain a good history and maintain high suspicion for carcinoid tumor in cases of recurrent bowel obstructions.