Paraplegia caused by extraspinal metastasis from a uterine fibroid.

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 there has been invasion of blood vessels (Bell, 1924; Graham, 1925). Similarly the apparently innocent fibroid which metastasizes may, if minutely examined, be found to have the appearance of a sarcoma. Steiner (1939) reports a case with a benign appearance in the primary tumour and in the secondary deposit, but careful examination of the former showed invasion of veins. Occasionally, however, thorough examination of these metastasizing uterine tumours fails to reveal any typically malignant structure and the same well-differentiated and benign appearance is present in the metastases as in the primary tumour in the uterus.