Severe abdominal pain and diarrhea – unusual multiple myeloma presentation with a severe prognosis: a case report

Abstract Background Multiple myeloma is a hematologic disease with high mortality rates all over the world. The diagnosis has always been challenging since the first case was reported in 1844. For that reason the diagnostic criteria have evolved over years to include the features of the disease more comprehensively. Unusual presentations are infrequent and a diagnostic challenge. For this reason we report this rare case in which diarrhea and abdominal pain were the initial presenting symptoms of multiple myeloma with a plasmacytoma. Case presentation An 87-year-old Hispanic man with a past medical history of hypertension, diabetes, and constipation, presented to an emergency department complaining of severe generalized abdominal pain and profuse diarrhea for 3 days. A physical examination revealed generalized pallor and dehydration but no signs of abdominal peritoneal irritation. Laboratory tests revealed neutrophilia and an elevated total protein. He received intravenously administered fluids and antibiotics. His abdominal pain became localized in the infraumbilical area and a small mass was palpated on the right lower quadrant on subsequent examination. An abdominal computed tomography scan showed a tumor lesion surrounded by fluid collection and a computed tomography-guided biopsy of the lesion confirmed it to be a plasmacytoma. A bone marrow biopsy revealed plasmatic cell augmentation but his beta-2 microglobulin levels were inconclusive. The diagnosis of multiple myeloma was finally confirmed with urine immunofixation. Bortezomib was initiated to decrease disease progression, but unfortunately 4 days later he developed acute pulmonary edema, had a cardiac arrest, and died. Conclusions This case illustrates the protean initial manifestations of multiple myeloma and the importance of an accurate diagnosis. Our patient’s initial presentation with gastrointestinal complaints is rare and the plasmacytoma location is even rarer, providing a challenging diagnostic problem. Prompt recognition of multiple myeloma is critical to institute appropriate therapy and prevention of disease progression