Implantation metastasis after percutaneous transthoracic needle aspiration biopsy.

The risk of tumour spread at aspiration biopsy of pulmonary tumours through the needle track has been analyzed by reviewing the case histories of 1 264 patients with a malignant tumour demonstrated by needle biopsy. Only in one case did metastatic tumour growth develop at the site of the biopsy. The history of this case is presented and the available literature on the subject discussed.