Duodenal Ulcer with Massive Gastrointestinal Hemorrhage as an Initial Manifestation in Multiple Myeloma with Extramedullary Disease: A Case Report.

Plasma cell neoplasms are characterized by dysregulated proliferation of mature B cells, which can present with either single (solitary plasmacytoma) or systemic (multiple myeloma (MM)) involvement. MM with extramedullary plasmacytoma (EMP) is a rare disease that accounts for approximately 3-5% of all plasmacytomas. EMP with gastrointestinal (GI) system involvement is an even rarer entity, accounting for <1% of MM cases. We present a case of aggressive MM with EMP invading the duodenum, initially presented with massive upper GI hemorrhage and small bowel obstruction. A 67-year-old woman was admitted to our hospital owing to a lack of either gas or feces passage for 3 days. Abdominal distention and vomit with a high coffee ground content were observed for 24 h. The patient's condition was initially diagnosed as small bowel obstruction, upper gastrointestinal bleeding, severe anemia, acute renal failure, and hypercalcemia. Furthermore, an analysis of immunoelectrophoresis in the blood, bone marrow aspiration, and tissue biopsy supported the diagnosis of MM and EMP invading the duodenum, upper GI hemorrhage, and small bowel obstruction. Our study provided the possible involvement of MM and EMP in the differential diagnosis of patients with unexplained GI hemorrhage and small bowel obstruction. A thorough review of the literature regarding the association between MM, GI hemorrhage, and small bowel obstruction is presented in this study.