SYP and neuroendocrine carcinoma: Histological examination (See additional file 1: Histology of the primary tumor surgical specimen) confirmed a transmural small-cell carcinoma containing nests of abnormal tubular and glandular structures, associated with vessel invasion, abundant in mitotic figures and with high Ki67 proliferation index (90%), and showing immunohistochemical positivity for synaptophysin and chromogranin and lymph node involvement, consistent with a poorly differentiated neuroendocrine carcinoma of the gastrointestinal tract [6,7].