1434 A Rare Case of Multiple Myeloma Presenting as Pancreatic Plasmacytoma Causing Obstructive Jaundice

Abstract

INTRODUCTION: Extramedullary plasmacytomas represent a rare type of plasma cell tumors which can present outside of the bone marrow. Although extremely uncommon, they should be considered in the differential diagnosis when it comes to obstructive jaundice and pancreatic malignancy. Here, I present a case of obstructive jaundice caused by extramedullary plasmacytoma mimicking an adenocarcinoma, diagnosed by endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA). CASE DESCRIPTION/METHODS: A 72-year-old Caucasian male patient presented to our hospital with complaints of fatigue and painless jaundice. On admission, his liver biochemistries were abnormal with ALT 417, AST 414, ALP 1309, T bili 15.9, D bili 13.4, with normal lipase, amylase and WBC. CT abdomen was significant for a large mass adjacent to the pancreatic head along with multiple retroperitoneal and intra-abdominal nodules. Subsequently, patient underwent EUS with FNA of the pancreatic lesion. Tissue biopsy was positive for plasmacytoma. Follow up ERCP was unsuccessful as CBD could not be cannulated due to bulging papilla. As such, IR guided biliary drainage was placed with successful decompression of the biliary tree and corresponding improvement in liver biochemistries. Further workup showed evidence of widespread plasmacytomas including involvement of heart and bone. DISCUSSION: Pancreatic plasmacytomas remain a rare entity, with only five percent of all plasma cell tumors occurring outside of the bone marrow. This case documents a rare occurrence of visceral involvement of multiple myeloma, brought to clinical attention by atypical involvement of pancreatic head and body. Gastrointestinal plasmacytomas are usually limited to the liver and stomach, with only a limited amount of cases describing pancreatic involvement. Most reported cases describe microscopic plasma cell infiltration of the pancreas, making this presentation of a well-formed mass unusual. Availability of EUS and FNA sampling has made it easier for clinicians to diagnose plasmacytomas, as radiological differentiation of these tumors from other pancreatic malignancy is difficult. Furthermore, it is imperative to make the correct tissue diagnosis as prognosis and management differs from other pancreatic malignancy. This case highlights the importance of keeping a broad differential when suspecting a pancreatic malignancy in a patient with obstructive jaundice and those with history of plasma cell disorders.