Hassall's corpuscles are seen in

Corpuscles of Hassall - These are small rounded structures present in the medulla of the thymus. Each corpuscle has a central core formed by epithelial cells that have undergone degeneration. These cells ultimately form a pink staining hyaline mass. Around this mass there is a wall formed by concentrically arranged epithelial cells. These cells also stain bright pink with haematoxylin and eosin. The central mass of the corpuscle may also contain degenerating macrophages. REF : Inderbir Singh's Textbook of Human Histology, seventh edition, pg.no.,139.