A 49-year-old man with long-standing type II diabetes mellitus has had epistaxis for the past 2 weeks. Laboratory studies show:
Hemoglobin 8.0 g/dL
Platelets 180,000/μL
Bleeding time 11 minutes
Prothrombin time 12 seconds
Partial thromboplastin time 36 seconds
Blood urea nitrogen 90 mg/dL
Which of the following is the most likely cause of this patient’s epistaxis?
