An asteroid refers to an eosinophilic body exhibiting gradiating lines, observed in a vacuolated region of the cytoplasm of a multinucleated giant cell, mainly witnessed in sarcoidosis, however, also observed in other granulomas.
It is also considered as a structural feature of sporotrichosis when observed in the skin or in secondary lesions of sporotrichosis. Thus, in order to be considered as a cell, it must possess a nucleus and membrane-bound organelles.