Present status of spiculed red cells and their relationship to the discocyte-echinocyte transformation: a critical review.

A VARIETY OF RED CELLS with one or more spiny projections has been 1-1._ described and some of these spiculed cells have been associated with specific congenital or acquired hemolytic anemias. Of these, only sickle cells are well defined morphologically, etiologically, and pathogenically. Tear drop cells are sharply defined morphologically and have been associated most prominently with myelofibrosis, although they occur in other conditions : thalassemia and abnormal erythropoiesis, both congenital and preceding leukemia. Helmet’ and triangular2 cells of microangiopathic anemia have now been well characterized by experimental studies as being due to bisection of normal red cells by fibrin strands during intravascular coagulation or injury on diseased vessel walls or on foreign surfaces presented by intracardiac prostheses.3 4 There remains a group of spiculed red cells which have been variously designated as burr cells,2’5 spur cells,6 acanthocytes,79 or acanthroid cells.’0 Recent observations with the scanning electron microscope11’4 have provided new insights into the interrelationship of the spiculed cells occurring in a variety of diseases and artifactual distortions to which normal and abnormal red cells are equally subject. It is the purpose of the present paper to define the recognizable cell types morphologically, to discuss their pathogenesis, to define the precautions necessary to avoid artifactual distortion of normal or abnormal cells, and to attempt to reconcile a number of apparently contradictory findings on the origin of these spiculed cells.