A 9-year-old boy presents with his parents to the pediatrician for a yearly check-up. The patient’s mother notes that over the last few months her son has seemed increasingly fatigued. His growth curves are significant for head circumference at the 9th percentile, height at the 4th percentile, and weight at the 20th percentile. Vitals are notable for mild tachycardia, normotension, and normothermia. Physical examination is notable for low set ears, hypoplastic thumbs, and several large hypopigmented skin lesions.
Which of the following hematologic findings is most likely present in this patient?
C) Pancytopenia
This patient likely has Fanconi anemia, which is an inherited form of bone marrow failure. Most affected individuals present in early-mid childhood and have physical abnormalities such as short stature, cafe-au-lait spots, ear/eye malpositioning, and malformed thumbs.
Answer choice A: Increased HgbS, is incorrect. This describes sickle cell trait/disease. Although these patients may also present with fatigue due to increased hemolysis, physical deformities are uncommon. Digital manifestations of sickle cell disease may include dactylitis, but hypoplastic thumbs would be uncharacteristic.
Answer choice B: Normocytic anemia with eosinophilia, is incorrect. This finding may be present in individuals with Addison disease (primary adrenal insufficiency). Although these patients may also present with fatigue, additional symptoms such as hyperpigmentation, gastrointestinal distress, and hypotension are typically present.
Answer choice D: Pure red cell aplasia, is incorrect. This describes Diamond-Blackfan anemia. Although Diamond-Blackfan anemia can also present with short stature and craniofacial abnormalities, thumbs are typically triphalangeal. Additionally, onset of Diamond-Blackfan anemia is rapid and typically presents within the first year of life.
Answer choice E: Thrombocytopenia with hemolytic anemia, is incorrect. This describes hemolytic uremic syndrome (HUS) which is also accompanied by acute kidney injury. Patients with HUS typically present with overt signs of thrombocytopenia such as bleeding or bruising.
Key Learning Point
Fanconi anemia is an inherited bone marrow defect that leads to pancytopenia and is characterized by concomitant short stature, hypoplastic thumbs, and cafe-au-lait spots. It typically presents in early-mid childhood and may therefore be distinguished from Diamond-Blackfan anemia which is a pure red blood cell aplasia that presents in the first year of life.
