3001 A Rare Location for Signet Ring Cell Carcinoma

Abstract

INTRODUCTION: Roughly 96% of Signet Ring Cell Carcinoma (SRCC) occurs in the stomach. However, it has also been reported at extra-gastric locations such as the breast, colon, and gallbladder. Although still rare, the incidence of gastric signet ring cell carcinoma has been rising in the past decade and it is now being found in uncommon locations. Only 7 cases have been reported for the presence of a SRCC in pancreas. We report a case of pancreatic signet ring cell carcinoma which was diagnosed with EUS-guided biopsy. CASE DESCRIPTION/METHODS: Case A 71-year-old Caucasian male presented with diarrhea and abdominal pain for 1 month as well as a 10 lb weight loss over a 2-month period. Physical examination was positive for jaundice and initial labs showed a bilirubin of 9.8, AST 229, ALT 240, and alkaline phosphatase 420. MRI of the abdomen showed dilation of both the pancreatic duct and common bile duct (CBD), and a distal CBD stricture. The patient underwent an EUS, which showed a 2.8 cm × 2.5 cm hypoechoic ill-defined mass in the head of the pancreas with poorly defined, irregular borders. A 22-gauge needle was used to perform aspiration with four needle passes. ERCP was then performed to place a 10 Fr plastic stent across the CBD stricture. Pathology of the pancreatic mass aspiration revealed moderately to poorly differentiated adenocarcinoma with signet ring cell features. PET CT and abdominal CT were performed without evidence of distant metastasis. CA 19-9 levels were 352. Based on radiographic imaging and endoscopic ultrasound, the patient was staged IIA (T3N0M0) but was found not to be a surgical candidate due to multiple cardiopulmonary comorbidities and was started on neoadjuvant chemotherapy. DISCUSSION: The histopathology of SRCC in pancreas appears similar to that of the gastric variant in that the tumor is characterized by intra-cytoplasmic mucin vacuoles that expand the nucleus of the cell to the periphery. Little is known about the differences in prognosis and treatment. However, there is an overall poorer prognosis in patients with SRCC regardless of location. EUS guided biopsy provides a safe technique in the setting of co-morbidities which preclude surgery. Our case demonstrates the need for more research in SRCC on any location as well as targeted modalities for extra-gastric locations while also highlighting the usefulness of EUS as a tool for diagnosis.