A 43-year-old woman of Scandinavian descent complains of constant tiredness, light-headedness, and occasional palpitations and shortness of breath while ascending the stairs. Physical examination shows pallor of the oral mucosa and a raspberry-red tongue (glossitis). Neurologic examination reveals paresthesias, numbness, decreased vibration sensation, and loss of deep tendon reflexes. The results of laboratory studies include hemoglobin of 7.2 g/dL, WBC of 4,500/mL, platelets of 140,000/mL, erythrocyte folate of 220 ng/mL, serum vitamin B12 of 40 pg/mL (normal >200 pg/mL), serum anti-intrinsic factor of 1 :128, and serum anti-parietal cell antibody of 1 :64. Examination of peripheral blood shows macrocytic anemia, with poikilocytosis of RBCs and hyper segmented neutrophils. Atrophic gastritis is diagnosed by gastric biopsy. Bone marrow examination in this patient will reveal which of the following pathologic findings?
A 43-year-old woman of Scandinavian descent complains of constant tiredness, light-headedness, and occasional palpitations and shortness of breath while ascending the stairs. Physical examination shows pallor of the oral mucosa and a raspberry-red tongue (glossitis). Neurologic examination reveals paresthesias, numbness, decreased vibration sensation, and loss of deep tendon reflexes. The results of laboratory studies include hemoglobin of 7.2 g/dL, WBC of 4,500/mL, platelets of 140,000/mL, erythrocyte folate of 220 ng/mL, serum vitamin B12 of 40 pg/mL (normal >200 pg/mL), serum anti-intrinsic factor of 1 :128, and serum anti-parietal cell antibody of 1 :64. Examination of peripheral blood shows macrocytic anemia, with poikilocytosis of RBCs and hyper segmented neutrophils. Atrophic gastritis is diagnosed by gastric biopsy. Bone marrow examination in this patient will reveal which of the following pathologic findings?
💡 Explanation
## **Core Concept**
The patient's presentation suggests a diagnosis of **pernicious anemia**, a condition characterized by the deficiency of **vitamin B12** due to the lack of **intrinsic factor**, which is necessary for vitamin B12 absorption. This condition leads to **macrocytic anemia**, **neuropathy**, and other systemic symptoms.
## **Why the Correct Answer is Right**
The patient's low serum vitamin B12 level, presence of anti-intrinsic factor and anti-parietal cell antibodies, and the diagnosis of atrophic gastritis are all consistent with pernicious anemia. The bone marrow in pernicious anemia typically shows **megaloblastic changes** due to the impaired DNA synthesis. This results in the production of large, immature red blood cells (megaloblasts) that are not able to mature properly, leading to the characteristic **macrocytic anemia** seen in the peripheral blood.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option might suggest a different type of bone marrow finding not associated with pernicious anemia or vitamin B12 deficiency.
- **Option B:** Similarly, this could imply an alternative diagnosis such as iron deficiency anemia or another type of anemia not related to vitamin B12 deficiency.
- **Option C:** This option could represent a finding in a different condition affecting the bone marrow, such as a myeloproliferative disorder or another type of anemia.
- **Option D:** Assuming this is not the correct answer, it would imply a bone marrow finding not characteristic of pernicious anemia, such as those seen in aplastic anemia, leukemia, or lymphoma.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **pernicious anemia** is often associated with **autoimmune atrophic gastritis**, leading to the production of **anti-intrinsic factor** and **anti-parietal cell antibodies**. The presence of these antibodies, along with low vitamin B12 levels and megaloblastic anemia, is diagnostic. Treatment involves **lifelong vitamin B12 supplementation**.