Mixed neuroendocrine-non-neuroendocrine neoplasms of the right colon: a case report.

Mixed neuroendocrine-non neuroendocrine neoplasm (MiNENs) is a rare gastrointestinal neoplasm that has been redefined by the World Health Organization (WHO) in 2017 as the association of two types of components, neuroendocrine and non-neuroendocrine, each of them present in at least 30% of the tumour mass. Small case reports and case series have demonstrated the occurrence of this neoplasm in the colon. We here report the case of a 47-year-old man undergoing colonscopy for anemia. This showed impassable polypoidal tumor budding in the right colic flexure. Computerized tomography (CT) scan and magnetic resonance imaging (MRI) showed the presence of liver metastases. As the tumor was hemorrhagic, right hemicolectomy with lymph node dissection was performed. The histological examination showed MiNEN of the ascending colon. The patient received adjuvant chemotherapy.