Abstract
A tumor consisting of an adenocarcinoma component and a neuroendocrine carcinoma component, with each component accounting for at least 30% of the tumor, is defined as a mixed adenoneuroendocrine carcinoma (MANEC). We report a case of MANEC of the pancreas. A 63-year-old man presented with hyperglycemia and was referred to our hospital for further examination. Abdominal contrast-enhanced computed tomography (CT) revealed a mass of 2 cm in size in the pancreas head with portal vein narrowing. Fluorin-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) CT revealed increased accumulation in the mass of the pancreas head. Endoscopic retrograde cholangiopancreatography (ERCP) showed severe narrowing of the main pancreatic duct. Cytological analysis by endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) suggested a neuroendocrine tumor. Under the diagnosis of neuroendocrine tumor, pancreaticoduodenectomy with portal vein resection and regional lymph node dissection was performed with curative intent. Histological examination revealed that the tumor consisted of two cell populations. One was well- to moderately differentiated tubular adenocarcinoma. This cell component accounted for 45% of the whole tumor. The second component was non-adenocarcinoma cells arranged in a nest, and the cells had round nuclei, abundant cytoplasm, and coarse chromatin. The Ki67 labeling index was 40%. Immunohistochemically, the adenocarcinoma cells were positive for CEA but negative for chromogranin A (CgA) and synaptophysin (Syn), while the non-adenocarcinoma cells were positive for the expression of CgA and Syn but negative for CEA. Based on the findings, a diagnosis of MANEC of the pancreas was made. Postoperatively, lymph node metastasis and peritoneal dissemination developed rapidly and he died the 6 months after the operation. Due to the small number of reported cases of MANEC of the pancreas, its clinical behavior remains unclear and a standardized management protocol has not been established. Further investigation of more cases of this rare entity is necessary.
Highlights
In the 2010 World Health Organization (WHO) classification of neuroendocrine neoplasms in the digestive system [1], tumors consisting of an adenocarcinoma component and a neuroendocrine carcinoma component, in which each component accounts for at least 30% of the tumor, are defined as mixed adenoneuroendocrine carcinomas (MANECs) [1]
The adenocarcinoma cells were positive for Carcinoembryonic antigen (CEA) but negative for chromogranin A (CgA) and synaptophysin (Syn), while the non-adenocarcinoma cells were positive for the expression of CgA and Syn but negative for CEA (Fig. 4a–c)
The term MANEC was introduced by the 2010 WHO classification of neuroendocrine neoplasms in the digestive system [1]
Summary
In the 2010 World Health Organization (WHO) classification of neuroendocrine neoplasms in the digestive system [1], tumors consisting of an adenocarcinoma component and a neuroendocrine carcinoma component, in which each component accounts for at least 30% of the tumor, are defined as mixed adenoneuroendocrine carcinomas (MANECs) [1]. MANECs can occur in various organs including the gallbladder [2], bile duct [3], stomach [4], colon [5], and cecum [6] This classification applies to pancreatic neuroendocrine neoplasms. Case presentation A 63-year-old man presented with hyperglycemia and was referred to our hospital for further examination in April 2015 He had no past history including pancreatic disorders. The portal vein showed narrowing, suggestive of tumor invasion (Fig. 1). FDG-PET CT revealed increased accumulation in the mass of the pancreas head (Fig. 2a). Histological examination revealed that the tumor consisted of two cell populations (Fig. 3). The patient’s postoperative course was eventful, and he was discharged on the 34th day after the operation He underwent adjuvant chemotherapy consisting of a combination irinotecan and cisplatin. Lymph node metastasis and peritoneal dissemination developed rapidly, and he died 6 months after the operation
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