Multiple myeloma presenting with digital gangrene and renal impairment in a frail older adult: A case report

Multiple myeloma (MM) is a plasma cell malignancy that primarily affects the elderly, with high mortality rates. MM can present with a wide range of clinical manifestations. While common features include anaemia, renal dysfunction, bone pain, and hypercalcaemia, atypical presentations may delay diagnosis and affect outcomes. We report the case of a 74-year-old frail man with multiple comorbidities who presented with progressive digital gangrene and worsening renal function. Initial investigations ruled out peripheral arterial disease and raised the possibility of vasculitis. However, serum and urine electrophoresis revealed monoclonal kappa light-chain gammopathy. The bone marrow biopsy confirmed the diagnosis of MM, while imaging revealed spinal lytic lesions. Renal biopsy revealed both cast nephropathy and membranoproliferative glomerulonephritis. Patient refused chemotherapy, and while on supportive care, he died of sepsis and renal failure. This case highlights an unusual presentation of MM, emphasising the fact that apart from vasculitis, monoclonal gammopathies should also be considered as a differential diagnosis for digital ischaemia and renal impairment in older patients. Furthermore, it emphasises the significance of integrating the patient’s functional status, comorbidities, and treatment preferences into clinical decision-making. In frail older adults, shared decision-making ensures that care remains patient-centred, appropriate, and ethically grounded.