A Missed Clue in Plain Sight: Hyperproteinemia and Nonlytic Skeletal Disease Revealing Immunoglobulin A Multiple Myeloma

IgA multiple myeloma can present with atypical and misleading clinical features, delaying diagnosis when more common conditions dominate the initial presentation. We report the case of a 50-year-old male with a history of recurrent gastrointestinal bleeding who presented with severe symptomatic anemia requiring transfusion. Initial evaluation focused on suspected acute blood loss; however, persistent cytopenias and markedly elevated total protein with a preserved albumin level raised concern for an underlying systemic process. Further laboratory evaluation revealed a significant globulin gap, with total protein levels exceeding 10 g/dL and markedly elevated immunoglobulin A (IgA) at 6,318 mg/dL. Serum free light chain analysis demonstrated elevated kappa chains with a profoundly abnormal kappa/lambda ratio. Imaging studies identified multiple vertebral compression fractures and diffuse osteopenia, while endoscopic evaluation revealed severe esophagitis without active bleeding to fully account for the degree of anemia. Bone marrow biopsy confirmed clonal plasma cell proliferation consistent with IgA multiple myeloma. This case underscores the diagnostic importance of recognizing hyperproteinemia and the globulin gap as early indicators of plasma cell dyscrasia, particularly in patients with competing clinical diagnoses such as gastrointestinal bleeding. It further highlights how multiple myeloma may present without classic features such as renal dysfunction or hypercalcemia, instead manifesting through indirect findings, including skeletal fragility and unexplained cytopenias. Early recognition of these subtle but critical clues can facilitate timely diagnosis and initiation of therapy, ultimately improving patient outcomes.