21 - echinocyte ( burr cell )

Definition:

Red cell membrane abnormality characterized by short, blunt projections (spicules) of relatively uniform length and evenly distributed over the red cell surface. In early stage of development the red cell maintains a discoid shape (echinocyte I), but may progress to a spherical shape (echinocyte IV, spheroechinocyte).

Pathobiology:

Due to an expansion of the outer leaflet of the lipid bilayer, and the abnormality is reversible.

Differential Diagnosis:

• Artifact- blood smear improperly prepared, usually due to a delay in the preparation of the blood smear from EDTA-anticoagulated blood sample.
• Aging of red cells in vitro, e.g. transfused blood- due to ATP depletion and lysolecithin formation.
• Renal insufficiency
• Impact hemolysis
• Liver disease
• Hypophosphatemia and hypomagnesemia (malnutrition)
• Pyruvate kinase deficiency
• Severe burns

20 - dacrocyte

Dacryocyte is a pear-shaped or tear-shaped red blood cell that is usually seen in a broad spectrum of infiltrative disorders that disrupt the bone marrow architecture and also in extramedullary hematopoiesis.hence it is called TEAR DROP CELL .

The abnormality is thought to be due to membrane damage to the red cell during maturation in a crowded bone marrow environment, damage at the time of exit from the bone marrow and subsequent circulation through the spleen.

These cells are usually seen in disorders such as myelofibrosis, metastatic tumor in the bone marrow, extramedullary hematopoiesis, dyserythropoiesis, megaloblastic anemias, thalassemia especially in thalassemia major, acute leukemias, and in multiple myelomas.