Cellular Biology of Teratoma

Teratomas are bizarre tumours which contain multiple tissues of kinds foreign to the part of the body in which they arise. Within teratomas these tissues can be organised into recognisable organs, limbs and, in some instances, structures which resemble a complete fetus (1,2,3). These 'monstrous' features give these tumours their name (teras=monster, in Greek). A common example of this bizarre differentiation is the production of hair and skin within benign ovarian teratomas (Fig. 1). The nature of teratomas is due to the fact that they arise from pluripotent cells, i.e. early enbryonic cells or primordial germ cells. Thus a teratoma can contain tissues which are derived from all three embryonic cell layers, and this constitutes the strictest definition of a