Long-term survival with complete remission after irinotecan plus cisplatin therapy for metachronous liver metastasis from a gastric mixed neuroendocrine-non-neuroendocrine neoplasm: a case report.

Gastric mixed neuroendocrine-non-neuroendocrine neoplasm, which consists of both exocrine and endocrine components, is rare and exhibits aggressive biological behavior and poor prognosis. A 64-year-old man underwent investigation for abdominal pain. An endoscopic examination revealed a 30-mm protruded lesion in the gastric antrum for which distal gastrectomy with lymph node dissection was performed. Histopathological examination showed two distinct components, an adenocarcinoma component and neuroendocrine carcinoma component, with immunohistochemical staining positive for CD56, chromogranin A, and synaptophysin. The final diagnosis was mixed neuroendocrine-non-neuroendocrine neoplasm, pT2, pN3, M0, stage IIIA. Multiple liver metastases were detected 3 months after surgery. The patient received irinotecan plus cisplatin therapy, which was effective, and the liver metastases disappeared. The patient remains alive, without any recurrence, more than 10 years after surgery. We present a rare case of gastric mixed neuroendocrine-non-neuroendocrine neoplasm and review the literature to contribute to improving our understanding of this kind of tumor.