Multiple primary cancers of the esophagus and thyroid gland

The occurrence of multiple primary cancers in the aerodigestive tract is a well known phenomenon that has been explained by the concept of 'field carc inogenesis'. Metachronous or synchronous esophageal cancer has usually been identified in patients with head and neck cancer, gastric cancer or colon cancer. The incidence of multiple primary cancers of the esophagus and thyr oid gland is very low. We treated four patients with synchronous cancers of the cervical esophagus and the thyroid gland. Histologically, all of the e sophageal cancers were squamous cell carcinomas. Thyroid cancers were evalu ated as papillary carcinoma or follicular carcinoma. Both the esophageal ca ncer and the thyroid cancer frequently metastasized to lymph nodes. All pat ients had multiple lymph nodes metastasis from the esophageal or the thyroi d cancer. In one patient, both the esophageal and the thyroid cancers were detected in the same lymph node. Three of four patients died from recurrenc e of esophageal cancer. The prognosis of these patients was poor. In the tr eatment of esophageal carcinoma, cancers of other organs including the thyr oid gland should be carefully investigated.