Abstract
Herein we report a case of mixed adenoneuroendocrine carcinoma of the stomach. An 80-year-old man was referred for treatment of early gastric cancer detected by periodical medical assessment. Using upper gastrointestinal tract endoscopy, an irregular elevated tumor was observed at the lesser curvature of the lower third of the stomach. Pathological examination of biopsy specimens revealed well-differentiated tubular adenocarcinoma (tub1). Although pretreatment diagnosis was early gastric cancer (type 0-I) invading to the submucosal layer (SM2), diagnostic endoscopic submucosal dissection (ESD) was carried out as the patient declined curative surgery. Pathological examination of the ESD specimen demonstrated mucinous carcinoma together with tub1. In addition, at the deepest part of the tumor (SM1), neuroendocrine carcinoma was observed; immunohistochemistry revealed positive staining for synaptophysin, chromogranin A, and CD56. Using the latest WHO NET classification, we diagnosed the tumor as mixed adenoneuroendocrine carcinoma. Furthermore, vascular involvement (ly2 and v1) was observed in the neuroendocrine carcinoma. Additional resection was recommended but the patient declined to re-visit. Fourteen months later, he presented with general malaise. Upper gastrointestinal tract endoscopy revealed a tumor at the ESD scar site and pathological examination of biopsy specimens confirmed recurrence of neuroendocrine carcinoma. Concurrently multiple liver metastases, peritoneal disseminations and lymph nodes metastases were observed, and best supportive care policy was elected until the patient died eighteen months after the ESD.
