Midgut neuroendocrine tumor presenting with acute intestinal ischemia

Abstract

Neuroendocrine tumors represent a heterogeneous group of neoplasms that arise from neuroendocrine cells and secrete various peptides and bioamines. While gastrointestinal neuroendocrine tumors, commonly called carcinoids, account for about 2/3 of all neuroendocrine tumors, they are relatively rare. Small intestine neuroendocrine tumors originate from intestinal enterochromaffin cells and represent about 1/4 of small intestine neoplasms. They can be asymptomatic or cause nonspecific symptoms, which usually leads to a delayed diagnosis. Imaging modalities can aid diagnosis and surgery remains the mainstay of treatment. We present a case of a jejunal neuroendocrine tumor that caused nonspecific symptoms for about 1 year before manifesting with acute mesenteric ischemia. Abdominal X-rays revealed pneumatosis intestinalis and an abdominal ultrasound and computed tomography confirmed the diagnosis. The patient was submitted to segmental enterectomy. Histopathological study demonstrated a neuroendocrine tumor with perineural and arterial infiltration and lymph node metastasis. The postoperative course was uneventful and the patient denied any adjuvant treatment.

Keywords: Carcinoid; Enterectomy; Enterochromaffin cells; Jejunum; Pneumatosis intestinalis; Small intestine.

Figure 1

Plain abdominal X-ray depicts slightly dilated small bowel loop with pattern of intramural pearls of air (black arrows).

Figure 2

Sonographic features show dilated small bowel loop with absent peristalsis. Also depicted are increased intraluminal secretions within the ischemic small bowel segment (white arrow), slight mural thickening and intramural gas (black arrows).

Figure 3

Axial contrast enhanced computed tomography demonstrates intestinal pneumatosis (long black arrow).

Figure 4

Axial contrast enhanced computed tomography demonstrates a homogeneous thickened soft tissue mass at the small bowel mesentery (long black arrows), as well as intestinal pneumatosis (small black arrows).

Figure 5

Intraoperative findings.

Figure 6

Gross pathology specimen of resected small bowel, showing ischemic bowel and enlarged mesenteric lymph nodes.

Figure 7

Histopathological findings. A: Vascular and perineural invasion of tumor cells (blue arrows), medium magnification (100 ×); B: Tumor cells with characteristic nuclear appearance, high magnification (400 ×); C: Immunohistochemical staining reveals strong positivity for chromogranin A marker, high magnification (400 ×); D: Less than 1% of tumor cells reveal positivity for proliferative marker Ki-67, high magnification (400 ×); E: Immunohistochemical staining reveals strong positivity for CD56 marker, high magnification (400 ×); F: Immunohistochemical staining reveals strong positivity for synaptophysin marker, high magnification (400 ×).