An unusual case of papillary carcinoma of the thyroid with cutaneous and breast metastases only.

Cutaneous metastases of thyroid carcinoma are infrequent and, when present, are usually located in the vicinity of a widespread primary tumor. Breast metastases from these tumors are even less common. We report the case of a 64-year-old female with a toxic multinodular goiter in whom a fine-needle biopsy, performed in 1985 at the age of 52, was suggestive of papillary carcinoma of the thyroid. Total thyroidectomy for a papillary carcinoma, follicular variant, was performed in 1988. Four months after surgery, a cutaneous metastasis was discovered in the right thigh. Surgical excision of the lesion followed by treatment with radioactive iodine decreased serum Tg levels from 7495 to 3.3 micrograms/l. Under suppressive therapy with L-thyroxine, serum Tg remained undetectable for the next 4 years. Then, serum Tg levels rose to 3.9-5.6 micrograms/l and a second cutaneous metastasis was removed from the abdominal wall. The patient was again treated with radioactive iodine and the post-treatment whole-body scan did not show any area of increased uptake of the radionuclide. However, serum Tg levels under suppression with L-thyroxine remained elevated at 4-20 micrograms/l for the next 2 years. In August 1995, a 1.5 cm nodule was found in the right breast. Cytological examination was suggestive of a breast metastasis from thyroid carcinoma and the lesion was removed by enucleation. This proved to be a metastasis from a papillary carcinoma of the thyroid. Elevated (19-44 micrograms/l) serum Tg levels persisted postoperatively. A third cutaneous metastasis was revealed by 131I scintigraphy in the right buttock and surgically removed in December 1996. Serum Tg levels have remained undetectable since then. To the best of our knowledge, this is a unique case of a papillary carcinoma of the thyroid with a propensity to metastasize only to the skin and breast during a follow-up of 11 years.