A Rare Presentation of a Duodenal Neuroendocrine Tumor.

Neuroendocrine tumors (NETs), which are a rare type of tumor, are defined as epithelial cells with predominantly neuroendocrine differentiation and consist of a spectrum of tumors emerging from stem cells throughout the body and can occur anywhere in the body. While they are rare, the incidence over the past few decades has increased. Here we present a case of a 64-year-old female who was incidentally found to have a duodenal neuroendocrine tumor. The patient initially presented to the emergency department secondary to syncope and collapse. During her trauma evaluation, an incidental lobulated soft tissue mass inferior to the distal stomach was seen on complete computed tomography (CT) scans. The surgery team was consulted for resection of the mass and an octreotide scan was performed prior to resection to further evaluate the mass and to check for any signs of metastatic disease. The octreotide scan demonstrated intense radiotracer accumulation within the duodenal mass consistent with a neuroendocrine tumor and no areas of abnormal radiotracer accumulation suspicious for metastatic disease. Pathology of the resected mass was positive for a well-differentiated neuroendocrine tumor with an organoid pattern and homogenous oval-round neoplastic cells with a salt-pepper nuclear and pseudo glandular arrangement that was well-circumscribed and partially encapsulated with negative margins. Immunohistochemistry was positive for AE ⅓, CD56, Synaptophysin, and chromogranin and negative for CD117, DOG-1, CD34, and CD45. The prevalence of NETs has increased over the years due to the improvement in diagnostic tools, such as upper gastrointestinal endoscopy. In addition to the fact that the duodenum is a rare location for such tumors, neuroendocrine tumors are also typically found in those under 50 years old. However, our patient was found to have both a duodenal mass and was over the age of 50 at the time of presentation and diagnosis. To date, a consensus on a conclusive treatment of duodenal NETs (D-NETs) has not been reached. This case brings to light the importance of further research in diagnosing and treating neuroendocrine tumors and also raises awareness for clinicians to have this in their differential.