Polyclonal Hypergammaglobulinemia Associated With Multimorbidity and Malnutrition in an Elderly Man: A Comprehensive Diagnostic Approach.

A 76-year-old man with a history of liver cirrhosis, chronic obstructive pulmonary disease (COPD), secondary adrenal insufficiency, and psychiatric comorbidities presented with severe weight loss and laboratory findings of pancytopenia, hypoalbuminemia, and IgG-predominant hypergammaglobulinemia, raising suspicion for multiple myeloma. However, serum protein electrophoresis, immunofixation, and urinary Bence Jones testing showed no monoclonal protein, and the kappa/lambda (κ/λ) ratio remained normal, indicating polyclonal hypergammaglobulinemia. Further evaluation revealed decompensated liver cirrhosis with hypersplenism, secondary adrenal insufficiency, severe obstructive ventilatory defect from COPD, and nutritional deficiencies. Management included nutritional supplementation, infection control, diuretics, hydrocortisone replacement, and branched-chain amino acids, leading to gradual improvement and discharge with preserved daily function. This case illustrates how multimorbidity, malnutrition, and disuse can mimic malignant conditions, producing hypergammaglobulinemia and weight loss through chronic systemic inflammation. It emphasizes the importance of considering non-malignant causes, especially in frail older patients, and highlights the need for a comprehensive diagnostic and management approach that integrates chronic disease care, nutritional support, and community-based interprofessional collaboration.