Three eccentrocytes from a dog with onion toxicity. A shrunken echinocyte and a fragmented cell are present as well, probably also reflecting oxidant injury.
Eccentrocytes are red cells with a ragged appearing, poorly hemoglobinized fringe of cytoplasm along one side of the cell. Also known as "hemi-ghost" cells and "pseudo-spherocytes", this appearance results from an apposition and adherence of opposing inner surfaces of the cell membrane in this area (which variably excludes hemoglobinized cytoplasm to an "eccentric" location in the cell).
      Eccentrocytes form under conditions of excess oxidant stress to the erythrocytes, which induces crosslinking of membrane proteins. Often, they are seen in association with Heinz bodies, which provide evidence of an oxidant effect on hemoglobin.
      Such cells have been seen in association with sydromes of oxidant injury in dogs, cats, and horses (e.g. onion and red maple leaf toxicity, glucose-6-phosphate dehydrogenase deficiency).

Scanning EM of a pyknocyte, with a membrane tag

Reproduced with permission from Harvey et al, Vet Pathol, 2003:636.

Eccentrocytes can also be seen in animals with fragmentation anemia, together with keratocytes and schistocytes.
Note that when the thin membrane of the eccentrocyte is removed or ruptures, a small cell which lacks central pallor is formed. These spherocytic cells are termed "pyknocytes" and can be mistaken for spherocytes under light microscopy. Electron microscopy usually reveals the membrane "tags" (whereas spherocytes are uniformly spherical) as shown in the image on the left.