Teratoma cancer cells. Coloured scanning electron micrograph (SEM) of teratoma cancer cells. This cancer arises from the germ (sex) cells and is therefore found in the ovaries in women and the testes in men. Because germ cells are pluripotent, that is they can differentiate into any cell type, tumours contain a mixture of tissues. Hair and teeth may grow in the tumour. The prognosis is generally better for females than for males.