ALTHOUGH the gastrointestinal tract is the commonest site of carcinoma, the number of cases reported in which tumors from the gastrointestinal tract have spread to the thyroid gland is extremely small. Because we recently encountered a case of carcinoma of the rectum metastatic to the thyroid gland, we were led to examine the literature for other instances, and to date four such cases have been reported.
In 1939 Willis1 collected 47 recorded cases of metastatic growths in the thyroid gland, of which 1 from the rectum was reported by Naegeli2 in 1922. Willis added and described 10 personal cases, including another in which the primary tumor was in the rectum. In 1936 Rankin and Fortune3 reported a case of carcinoma of the rectum in detail, which revealed, in addition to the customary metastases, one in the thyroid gland. At the Mayo Clinic4 the collected cases until