GASTRIC CARCINOMA BETWEEN HIGH GRADE NEUROENDOCRINE FEATURES AND ADENOCARCINOMA: A CASE REPORT AND BRIEF REVIEW OF LITERATURE

Mixed adenoneuroendocrine carcinoma (MANEC) is an exceptionally rare type of cancer associated to the gastrointestinal tract, without a clearly established and optimal therapeutic management. These tumors present with non-specific symptoms or histopathological findings to distinguish them from pure adenocarcinomas. We report the case of a 64-year-old male diagnosed with a high grade mixed adeneuroendocrine carcinoma of the gastric antrum, stage T2N3Mx. The patient underwent radical gastrectomy and the histopathological examination of the surgically resected specimen revealed a tumor mass containing both adenocarcinoma and poorly differentiated neuroendocrine components. Immunostaining for Chromogranin A and Synaptophysin was positive in the neuroendocrine component and negative in the adenocarcinoma component, which was positive for CK7 and CK20. Ki67 proliferation index was 95%. Using this report as reference, we also discuss the imunohistopathological features, clinical behavior and therapeutic management of mixed adenoneuroendocrine carcinomas, presenting a brief review of literature regarding this rare, yet highly aggressive tumor.