S3409 Features of Recurrent Mechanical Obstruction With Nonobstructive Duodenal Neuroendocrine Tumor

Abstract

Introduction: Primary duodenal neuroendocrine carcinoma (NEC) is a rare and highly aggressive malignancy with very poor prognosis. There is no established treatment due to its rarity. Treatment regimens used for small cell lung cancer (SCLC) are used to treat neuroendocrine carcinoma, due to its clinical and histopathological similarities. Therapeutic strategies are poorly understood and not well defined. There is no standardization of therapy even for limited disease and usually multimodal treatment approach is used. Etoposide based treatment regimens have been used mostly in advanced stages. We herein report a case of an aggressive primary duodenal neuroendocrine tumor with excellent response to oxaliplatin-based chemotherapy regimen. Case Description/Methods: We describe a case of a 72-year-old caucasian male who presented to emergency room with abdominal bloating and constipation. He was found to have peritoneal carcinomatosis and marked hydronephrosis in computed tomography (CT) of the chest/abdomen/pelvis. He was further evaluated by urology, oncology, and gastroenterology team. He had paracentesis with removal of 4 L of ascitic fluid. He underwent esophagogastroduodenoscopy, endoscopic ultrasound, and a colonoscopy for further assessment. He was found to have a large mass in the duodenum which upon biopsy was consistent with grade 4 poorly differentiated neuroendocrine carcinoma. Positron emission tomography dotadate scan, peritoneal biopsy and peritoneal fluid cytology further confirmed metastatic neuroendocrine carcinoma. His tumor markers showed elevated Ca 19-9 and chromogranin levels at presentation. Due to his poor performance status and concerns for intolerability to etoposide, he was started on FOLFOX chemotherapy. He completed 12 cycles of chemotherapy with near complete resolution of his disease as evidence by his positron emission tomography dotadate scan and improvements in his tumor markers. Due to excellent response and disease remission, he is currently on xeloda with omission of oxaliplatin. Discussion: Primary duodenal neuroendocrine carcinoma is a relatively rare malignancy with reported incidence of 0.4-2% among all duodenal malignancies. The prognosis is dismal due to presentation as advanced stage at diagnosis. Oxaliplatin based regiments have been shown to have promising anti-tumor activity in gastrointestinal neuroendocrine cancers, however the available data in duodenal gastrointestinal neuroendocrine cancers are very limited.