Complex sentence: Curschmann's spirals refers to a microscopic finding in the sputum of asthmatics which are spiral shaped mucus plugs from subepithelial mucous gland ducts or bronchioles.
Split into simpler sentences: Curschmann's spirals are a microscopic finding in the sputum of asthmatics. They are spiral-shaped mucus plugs from subepithelial mucous gland ducts or bronchioles.