Synchronous double cancers of colonic large cell neuroendocrine carcinoma and gastric squamous-cell carcinoma: a case report and review of literature.

Either colonic large cell neuroendocrine carcinoma (LCNEC) or gastric squamous-cell carcinoma (SCC) is extremely rare, with a very poor prognosis due to the high rate of distant metastases. Here, we report the first case of synchronous double malignancies in form of colonic LCNEC and gastric SCC. A 66-year male underwent a right hemicolectomy for a mass obstructing the ascending colon and an emergent gastroscopic hemostasis for another hemorrhagic stomach mass. Histopathological examination confirmed colonic LCNEC displaying the characteristic of large, vesicular nuclei with variable amounts of cytoplasm and gastroscopic biopsy revealed poorly-differentiated gastric SCC. Immunohistochemical staining of LCNEC demonstrated positive activities for chromogranin A, synaptophysin, CD56, NSE, ki-67 (>95%), but negative for CD99, CK20 and TTF-1. The patient had suffered from an accelerated growth of multiple liver metastases after surgery, suggestive of concomitant tumor resistance (CR), and survived 2 months after discharge.