RESUMEN
BACKGROUND: Multiple myeloma is one of the most common hematologic malignancies. Acquired factor X deficiencies are often observed in primary (AL) amyloidosis and rarely in multiple myeloma. OBJECTIVE: We report a case of an acquired factor X deficiency in a patient with a newly diagnosed IgA lambda multiple myeloma, without any evidence of concomitant amyloidosis. METHODS: We present the patient's medical history, clinical and physical examinations, laboratory analysis, and outcome. RESULTS: A 76-year-old male presented at the emergency department with ongoing gingival bleeding. Several analytical problems with blood sample analysis arose, which eventually led to the diagnosis of a multiple myeloma. Further exploration revealed an acquired factor X deficiency, explaining the ongoing bleeding. There was no evidence of concomitant amyloidosis. The multiple myeloma was treated, leading to complete remission of the malignancy and bleeding tendency. CONCLUSION: While coagulopathy is rarely observed in patients diagnosed with multiple myeloma, considering an acquired factor X deficiency becomes relevant when such patient present with bleeding diathesis.