Metastases of breast cancer to the thyroid gland in two patients - a case report.

Introduction: Metastatic cancer is rarely found in the thyroid (only 2-3% of malignant tumours found in that gland); primary sources usually including breast, kidney, and lung tumours.

Cases Reports: Two cases of advanced breast cancer with thyroid metastases in female patients are presented. The similarities between these two cases included: 1) postmenopausal age; 2) diagnosis based on result of FNAB (numerous groups of cells with epithelial phenotype strongly implying metastatic breast cancer); 3) thyroid function - overt hyperthyroidism in the first woman and subclinical hyperthyroidism in the second one; 4) the presence of nodular goitre in clinical examination, the occurrence of many nodular solid normoechogenic lesions with calcifications in both thyroid lobes in US; and 5) negative antithyroid antibodies. The main difference was the time of establishing diagnosis; in the first woman - before mammectomy, parallel to diagnostics of breast tumour, and in the second woman four years after mammectomy, during cancer dissemination (with right pleural effusion and lung metastasis). In the first case, mammectomy was followed two weeks later by thyroidectomy. The second patient was disqualified from thyroid surgery due to systemic metastatic disease.

Conclusions: 1. Fine needle aspiration biopsy of the thyroid gland should obligatorily be performed in patients with breast cancer and nodular goitre, even without any clinical data of metastatic disease. 2. The clinical context of cytological findings is of critical value. 3. In patients with breast cancer accompanied by multinodular goitre, we recommend that more punctures be performed during FNAB than is routinely done. (