Acquired FX Deficiency in Multiple Myeloma without Concomitant Amyloidosis: A Rare Case Report

Introduction: Acquired factor X (FX) deficiency is a rare coagulopathy. Occurrences in plasma cell dyscrasias (PCDs) independent of amyloid light-chain amyloidosis are exceedingly rare. Case Presentation: This case report presents a rare occurrence of acquired FX deficiency in a patient with multiple myeloma (MM) without concomitant amyloidosis. The patient, a 64-year-old male with prior diagnosis of smoldering MM, presented with abdominal pain and chronic bloody diarrheas and was diagnosed with absolute FX deficiency. Despite initial suspicion of amyloidosis, subsequent investigations ruled out its presence. Treatment with anti-myeloma therapy and supportive measures resulted in the normalization of coagulation parameters. Conclusion: This case underscores the importance of considering acquired FX deficiency in PCD patients presenting with coagulopathy even in the absence of amyloidosis.