Uterine fibroids are usually benign tumours, but occasionally, like some apparently benign thyroid tumours, they fail to behave as such and metastasize. " Benign metastasizing fibroid," like " benign metastasizing goitre" (Cohnheim, 1876), is a bad term, however, because it is self contradictory. There is evidence that the thyroid tumours are carcinomas and areas may be found in them where ther...