Multiple myeloma with extensive AL amyloidosis presenting as chronic diarrhoea

Abstract

We present a 52-year-old man admitted to the hospital with diarrhoea and lower extremity weakness ongoing for the past 3 months. The patient was found to have malabsorptive diarrhoea, hypoproliferative anaemia and renal insufficiency with proteinuria. Extensive workup was performed including a bone marrow biopsy with 20% plasma cells, renal and duodenal biopsies with Congo-red staining revealed amyloid deposition. The patient was diagnosed with multiple myeloma and amyloidosis with gastrointestinal, kidney and nerve involvement explaining his presentation with diarrhoea, renal insufficiency and weakness. Throughout his admission, there were incidental findings of asymptomatic hypoglycaemia (serum blood glucose <40 mg/dL), which was later found to be caused by anti-insulin monoclonal antibodies produced by the neoplastic plasma cells. This is an extremely rare manifestation of multiple myeloma with only a few cases reported in the literature.

Chronic Diarrhea as the Presenting Feature of Amyloidosis with Multiple Myeloma: A Case Report Diagnosed by a Myocardial Biopsy

“…MM is a neoplastic disease affecting plasma cells that is characterized by the clonal proliferation of malignant plasma cells within the bone marrow ( 18 ). The typical clinical manifestations of MM are hypercalcemia, renal insufficiency, anemia, and bone lesions ( 19 ).…”

Multiple Myeloma Presenting as Chronic Diarrhea

“… 8 Any region of the GI tract can be involved with amyloid infiltration, resulting in diarrhea, malabsorption, bleeding, or obstruction. 7 , 9 Another way MM can present is GI plasmacytoma, a tumor histologically identical to monoclonal plasma cells. Symptoms depend on the organ involved, but reports include obstruction, diarrhea, and abdominal pain.…”

“…5,6 In the presence of a known plasma cell neoplasm, unexplained GI symptoms could be a result of coexisting amyloidosis. 7 Over 10% of patients with MM have concomitant amyloidosis. 8 Any region of the GI tract can be involved with amyloid infiltration, resulting in diarrhea, malabsorption, bleeding, or obstruction.…”

Suggestive Diagnostic Process in a Case of Multiple Myeloma with Gastrointestinal Immunoglobulin Light-Chain Amyloidosis Accompanied by Protein-Losing Enteropathy

“…About 12%–15% of patients with MM will be found to have AL amyloidosis [ 1 ]. The kidney and heart are the most frequently involved organs in AL amyloidosis, whereas the gastrointestinal tract is rarely involved [ 2 , 3 ]. It is difficult to diagnose MM in the early stage because the clinical symptoms may be few or none at the initial phase of the disease.…”