Eosinophilic (Greek suffix -phil-, meaning loves eosin) is the staining of tissues, cells, or organelles after they have been washed with eosin, a dye.
Eosin is an acidic dye for staining cell cytoplasm, collagen, and muscle fibers.[1] [2] Eosinophilic describes the appearance of cells and structures seen in histological sections that take up the staining dye eosin.[2] Such eosinophilic structures are, in general, composed of protein.[3]
Eosin is usually combined with a stain called hematoxylin to produce a hematoxylin- and eosin-stained section (also called an H&E stain, HE or H+E section). It is the most widely used histological stain for a medical diagnosis.[3] When a pathologist examines a biopsy of a suspected cancer, they will stain the biopsy with H&E.
Some structures seen inside cells are described as being eosinophilic; for example, Lewy and Mallory bodies.[4] Some cells are also described as eosinophilic, such as Leukocytes.[5]