[Intrathyroid metastasis: 11 cases]

Non-thyroid cancers rarely metastasize into the thyroid gland. The aim of this retrospective study was to report a series of thyroid metastases and to emphasize their unusual occurrence and their poor prognosis.

Between January 1987 and June 1999 eleven patients underwent thyroidectomy for isolated, metastatic diseases of non thyroidal origin (mean age 61 yrs, 54.5% female). The primary tumors were: pulmonary squamous cell carcinoma (n=5), renal cell carcinomas (n=2), esophageal squamous cell carcinoma (n=1), leiomyosarcoma (n=1), oropharynx squamous cell carcinoma (n=1), and breast carcinoma (n=1). Analyzing these cases, there is a marked preponderance of lung cancers, renal cancer coming second in order of frequency. Clinical manifestations are: thyroid nodule without hormonal disturbance; others signs are dysphonia and/or dysphagia.

Ten patients underwent preoperative fine-needle aspiration, nine of ten were suggestive of metastatic disease. The mean time from resection of the primary tumor to thyroid metastases was 25 months (range 1-96 months). Total thyroidectomy (n=9) or lobectomy (n=2) was performed without morbidity or mortality. No patients have had recurrent disease in the neck. Median survival after treatment was 10 months (range 1-29 months). Course of death were mainly disseminated metastases.

For isolated metastatic cancer to the thyroid, surgical resection should be performed in order to avoid potential morbidity of tumor recurrence in the neck, even if the prognosis remains poor, for the majority of the cases.