Described by: Richard Cabot (American physician in 1903)
They are rarely seen; however when present their appearance is of violet coloured thin strands, that form single or double loops. Most often they are seen in polychromatic red cells.
Image: Cabot ring in 'figure of 8' appearance, within a pale (polychromatic) red cell
They reflect stressed or disordered haematopoiesis
Occasionally water entering during slide-fixation can cause a ring-like appearance affecting multiple cells, this will generally affect large numbers of cells.
These are residual microtubular structures that are believed to represent the remains of the mitotic spindle formed during cell division.