Needle tract seeding after percutaneous renal adenocarcinoma aspiration.

We report a rare case of tumor extension along a biopsy needle tract from renal cell carcinoma. Percutaneous renal mass aspiration has been reported to have a 3 to 4 per cent false positive rate and a 4 to 8 per cent false negative rate, and should be reserved for those renal masses in which a diagnosis is equivocal by noninvasive radiological techniques.