This patient was a middle-aged woman who was admitted to hospital with a history of weakness, palpitations, headache and lassitude for the previous 2 months. She also complained of a sore tongue. On examination there were signs of anaemia and cardiomegaly, and her skin was noted to have a pale yellow tinge.
The femoral shaft has been sawn longitudinally to show solid pale brown tissue replacing the normal yellow fatty marrow. This is an example of extension of haematopoietic marrow into the femoral shaft due to marked erythroid hyperplasia in a severely anaemic patient. Blood film and bone marrow aspiration biopsy showed the typical changes of megaloblastic anaemia.
Megaloblastic anaemia is so-called because of the great enlargement of the developing erythrocyte precursors in the bone marrow, and the enlarged mature red cells (macrocytes) in the peripheral blood. This condition may be caused by either vitamin B12 or folic acid deficiency. The latter is usually due to dietary deficiency or malabsorption. The former is usually due to chronic atrophic gastritis leading to pernicious anaemia. The lemon-yellow tinge described in the skin is due to premature death of large numbers of developing red cells in the bone marrow. This is called "ineffective erythropoiesis" and results in mildly increased serum levels of unconjugated bilirubin. This can be regarded as a form of extra-vascular haemolysis.