Unusual presentation of a neuroendocrine tumor in the ileostomy specimen after rectal cancer treatment: a case report

BACKGROUND: Neuroendocrine tumors of the small intestine are uncommon, but at the same time they are the most frequent subtype of neuroendocrine tumor in the gastrointestinal system. They originate from enterochromaffin cells, which are involved in the creation of serotonin. This asymptomatic characteristic in the initial presentation is usually why these tumors are discovered at a late stage, sometimes in association with symptomatic metastatic disease. CASE DESCRIPTION: We present a case-report of a 52-year-old gentleman with a suggestive family history of hereditary cancer syndrome (mother with lung cancer and maternal uncle with colon cancer at the age of 40 years old). The patient was diagnosed with rectal cancer and he received neoadjuvant chemotherapy with short-course radiotherapy followed by a robotic low anterior resection with diverting loop ileostomy. Following closure of his ileostomy, the pathology report of the ileostomy resection specimen showed a 1.1 cm neuroendocrine tumor with negative margins. CONCLUSIONS: This extraordinary unusual presentation could be very fortuity for the patient, who in every other opportunity just found this neuroendocrine tumor after advanced or maybe metastatic diseases.