Synchronous well differentiated ileal neuroendocrine tumour and colonic adenocarcinoma. A case report and a review of the literature

Synchronous colonic adenocarcinoma and well-differentiated ileal neuroendocrine tumour are infrequent and are usually incidental findings on autopsies or resected surgical specimens. Only rarely are they detected on colonoscopies or during surgery. We present a case of a synchronous caecal adenocarcinoma and well-differentiated ileal neuroendocrine tumour, undetected during colonoscopy, with carcinoid metastasis in one regional lymph node not associated with adenocarcinoma metastasis. A review of the literature shows that the association of non-synchronous second primary malignancies in patients with gastrointestinal carcinoid tumours is reported in more than 50% of cases; however, synchronous tumours are found in only 1-8%. It would appear that well-differentiated ileal neuroendocrine tumour could be a predisposing factor for the development of a second malignancy.