Collier's New Encyclopedia (1921)/Cyst

CYST (a bladder), a word sometimes used in the original sense as applied to hollow organs with thin walls, as the urinary bladder and gall-bladder; but commonly reserved for the designation of pathological structures or new formations within the body having the bladder form. Cysts may arise in two different ways: (1) either by the accumulation of products within cavities normally present, or (2) by the independent formation of a cavity. Of the first, wens, collections of secretion in a sebaceous gland of the skin, are the commonest example; instances of the second are cystic tumors of the ovary, and the sacs developed in connection with certain parasites. They are either simple or compound, unilocular or multilocular; they are sometimes small; in other cases they grow to an enormous size, and are very complex.