A 4-year-old male dies in the hospital from overwhelming infection. Autopsy findings include bone deformities and hepatosplenomegaly. Clumps of erythroid precursor cells are found in the liver and the spleen. The presence of these precursor cells is most likely related to which of the following conditions?

Question

A 4-year-old male dies in the hospital from overwhelming infection.  Autopsy findings include bone deformities and hepatosplenomegaly.  Clumps of erythroid precursor cells are found in the liver and the spleen.  The presence of these precursor cells is most likely related to which of the following conditions?

Quizplus · Accepted Answer

The presence of erythroid precursor cells in the liver and spleen is indicative of extramedullary hematopoiesis, a condition characterized by erythropoietin-stimulated, hyperplastic marrow cell invasion of extramedullary organs. Extramedullary hematopoiesis is most frequently caused by severe chronic hemolytic anemias, such as β-thalassemia (which the child depicted here may well have had). Extramedullary hematopoiesis can cause a range of skeletal abnormalities. The expanding mass of progenitor cells in the bone marrow thins the bony cortex and impairs bone growth. Pathologic fractures are common in the most symptomatic of children. Maxillary overgrowth and frontal bossing are associated with the characteristic "chipmunk facies" observed in the pediatric population. (Choice A) Red blood cell transfusions limit extramedullary hematopoiesis by reducing hypoxia. (Choice B) Immune deficiencies are not frequently associated with red blood cell hemolysis. (Choice C) Erythropoietin deficiency is observed in patients with chronic renal disease and would be associated with anemia, not extramedullary hematopoiesis. (Choice E) Iron deficiency results in a relative depression of erythropoietic activity and is not associated with extramedullary hematopoiesis. (Choice F) Cyanocobalamin (vitamin B₁₂) deficiency causes a megaloblastic anemia that is not associated with extramedullary hematopoiesis. (Choice G) Intrahepatic extramedullary hematopoiesis can cause portal hypertension, and portal hypertension can cause hepatosplenomegaly. The reverse is not true, however. Educational Objective: The presence of erythroid precursors in organs such as the liver and spleen is indicative of extramedullary hematopoiesis, a condition characterized by erythropoietin-stimulated, hyperplastic marrow cell invasion of extramedullary organs. Extramedullary hematopoiesis is most frequently caused by severe chronic hemolytic anemias, such as β-thalassemia.

A 4-Year-Old Male Dies in the Hospital from Overwhelming Infection