A case of a clinically silent mature teratoma of the uterine corpus is repo
rted. A 55-year-old woman presented with multiple uterine leiomyomas. The d
iscovery was incidental, because the patient was asymptomatic. Macroscopica
lly, a colloid-hemorrhagic-looking nodule was present. Histologic and immun
ohistochemical studies showed that this tumor was a small thyroid mass.