AFP and colonic neoplasm: By immunohistochemistry, the cells were positive stained for CD20, CDX-2, synaptophysin, and negative for AFP, CD7, CD56, neuron-specific enolase, and chromogranin A. Morphologic and immunohistochemical findings confirmed the diagnosis of poorly differentiated adenocarcinoma with neuroendocrine differentiation within the ascending colon tumor and mesenteric lymph nodes.