Needle tract implantation of papillary carcinoma of the thyroid following aspiration biopsy.

A case is reported of a slow-growing papillary carcinoma of the thyroid that caused clinically apparent implantation along the tract of a fine needle aspiration (FNA) biopsy. This appears to be the first report of a cutaneous needle tract metastasis from a papillary thyroid carcinoma. It represents a highly unusual complication of an FNA biopsy of an indolent, slow-growing tumor.