Two extragonadal teratomas in a mouse, with discussion of possible histogenesis

Abstract

Two spontaneous extragonadal teratomas were found in a 5-week-old female mouse, one in the upper abdomen and the other half-way along the tail. A wide variety of mature and immature tissues was encountered. Various aberrant structures occurred, the most remarkable being some cardiac muscle which formed an endothelial-lined structure resembling a chamber of a heart. As well as the two mid-line teratomas there was a mid-line congenital abnormality of the urogenital orifices and the anus. It is argued that the occurrence of a teratoma of the tail combined with the other mid-line tumour and a mid-line deficiency in organogenesis suggests that these extragonadal teratomas were derived from pluripotenital embryonic tissue which had escaped from embryonic organizers.