COLLISION ADENOCARCINOMA - LARGE CELL NEUROENDOCRINE TUMOR OF COLON : A CASE REPORT AND REVIEW OF LITERATURE.

Colorectal glandular-neuroendocrine mixed tumors are uncommon neoplams ; fewer than a hundred has been reported in the English literature until now. The first case was reported in 1924. They are classified into: collision tumors (side by side pattern) , amphicine tumors (both, neuroendocrine and glandular component in the same cell) and composite (intermingled). They are called “mixed” when the neuroendocrine component is at least 30%. We report a 64 year old male with an adenocarcinomalarge cel neuroendocrine tumor of colon, with collision pattern, in transverse colon which is an unfrequent location. The are two theories about these tumors: mature cells of different cell lines suffer from malignant changes or multipotent steam cell. The last one is the most accepted nowadays. Each component has an impact on the prognosis , because each of them can metastasize in an individual way, therefore, the most undifferentiated component will determine the prognosis. The most common place of metastases are lymphatic nodes and liver, and the metastases can have adenocarcinoma component, neuroendocrine component or both of them. Metastases from neuroendocrine component below 30 % have been reported. To sum up, colorectal glandular-neuroendocrine mixed tumors of colon are a heterogeneous and uncommon group of neoplasms. The knowledge of them is very important to avoid misdiagnosis.