Spherocytes are ball-shaped erythrocytes. Since they are usually small, they are also called microspherocytes. Unlike microcytes, they have no central pallor and usually have an elevated MCHC. Spherocytes have a reduced life span since they are mechanically-fragile. The ball-shape occurs because of a loss of cell membrane.
Spherocytes occur naturally in hereditary spherocytosis (a membrane defect) and acquired in hemolytic anemia (loss of cell membrane by immune mechanisms in the RES).