Review Question - QID 213738

A 30-year-old woman presents to the primary care clinic complaining of a 2-week history of lower extremity bruising. She also reports a 1-month history of fatigue. Her medical history is significant for polycystic ovary syndrome. She had surgery last year for a fractured clavicle following a sports injury. She takes a combined oral contraceptive pill. Her family history is significant for “blood issues,” but she is not sure of the specifics. On physical examination, bilateral conjunctivae are pale and there are multiple ecchymoses on the patient’s lower extremities. Labs are drawn, with results shown below:

Hemoglobin: 7.8 g/dL
Leukocyte count: 1000 cells/mm^3 with normal differential
Platelet count: 12,000/mm^3
Reticulocytes: 0.02%

A bone marrow biopsy is obtained, as shown in Figure A. Which of the following is the most likely cause of the patient’s presentation?