Echinocytes in gastric ulcer. Coloured Scanning Electron Micrograph (SEM) of abnormal red blood cells (echinocytes) in a patient suffering gastric ulcer. Echinocytes are red blood cells which become sea-urchin shaped" from their normal smooth surface and biconcave shape. They develop this spiked, crenated edge due to a plasmolysis reaction. When spherical in shape, as here, they may be called "sphero-echinocytes". Echinocytes often form at sites of medical disorders including gastric ulcer, and in cases of anaemia (haemolytic, sickle cell). Magnification: x5,600 at 6x7cm size. x7,150 at 4x5""