Eosinophilic

Eosinophilic (Greek suffix -phil, meaning eosin-loving) describes the staining of tissues, cells, or organelles after they have been washed with eosin, a dye commonly used in histological staining.

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]