Primary Ampullary Adenocarcinoma With Neuroendocrine Component in a BRCA-Positive Patient With Breast Cancer, an Exceedingly Rare Pathology: Case Report and Literature Review

INTRODUCTION: Periampullary tumors are cancers arising in the vicinity of the ampulla of Vater, originating from pancreas, duodenum, common bile duct or the ampulla itself. Primary ampullary cancers are extremely rare tumors occurring in four to six cases per million population. We present a case with primary ampullary adenocarcinoma in a patient with BRCA gene positive breast cancer status post bilateral mastectomy. CASE DESCRIPTION/METHODS: A 54-year-old female presented with epigastric pain of 2 weeks and associated weight loss. She had jaundice and severe epigastric tenderness. Blood work showed elevated All Phos(427) and Bilirubin(4.8). CT abdomen and pelvis showed CBD dilatation with distal obstruction and double duct sign. Her CEA and CA19-9 levels were 5.2 NG/ML and 282 U/ml. MRI showed moderate intra-and extrahepatic bile duct dilatation,CBD with 2.2 cm segment of severe narrowing related to soft tissue ampullary mass measuring 1.6 × 1.2 cm. EGD and ERCP showed extrinsic duodenal stenosis but papilla could not identified or cannulated. A Whipple’s resection was performed, with pathology showing invasive well differentiated ampullary adenocarcinoma (3.2 × 2.8 cm) pathological classification of pT3b pN1. Additionally it showed well-differentiated grade 1 neuroendocrine tumor, measuring 2 mm. post operatively she was seen by oncology. Her initial positron emission CT showed 7.8 mm spiculated nodule on her left lung. A surveillance PET scan 3 months later showed enlarging and cavitating lung nodules, so she was started on chemotherapy and successfully finished the treatment. However, after completing 6 months of chemotherapy she requested to terminate the treatment and let nature take its course. DISCUSSION: Primary ampullary adenocarcinoma account for 6% of periampullary cancers. Neuroendocrine tumors of ampulla of vater have a reported incidence of less than 0.3% and only 105 reported cases. Abdominal imaging followed by EGD and or ERCP is diagnostic method of choice. Treatment involves surgical resection followed by adjuvant chemoradiotherapy. The prognosis depends on histological subtype, staining pattern and nodal metastasis. Post-treatment surveillance to detect persistent or recurrent disease should be performed at regular intervals for at least 5 years. Our patient had node positive, pancreatobiliary phenotype with poor prognosis (5 year survival 20%).Figure 1.: Pathology slide of the duodenal lesion with underlying adenocarcinoma.