Solitary skin metastasis as the presenting feature of differentiated thyroid microcarcinoma: report of two cases.

Cutaneous metastases from thyroid neoplasia are very rare. Most patients presenting with such a disease have also both internal metastases and a very enlarged thyroid gland. We reported here 2 patients presenting with differentiated thyroid microcarcinoma which was revealed by a solitary scalp lesion. The positive immunoperoxidase staining for thyroglobulin (TG) in the skin tumour cells asserted the diagnosis of metastatic thyroid carcinoma. The thyroid neoplastic micronodular formation was unrecognized by ultrasonography and it was only found at serial histological examination of the thyroid gland entirely removed during surgery. Histological procedure showed a solitary follicular microcarcinoma (diameter = 0.5 cm) in 1 patient, and two differentiated microcarcinoma, a follicular microcarcinoma (diameter = 0.4 cm) in a lobe and a follicular-papillary carcinoma (diameter = 0.5 cm) in the other lobe, in the second patient.