We report the case of a 68-year-old male with extension of papillary renal cell carcinoma (Fuhrman grade III) along a percutanous biopsy tract detected at the time of partial nephrectomy. Biopsy was performed to a obtain tissue diagnosis of a complex renal cyst as the patient was unable to receive intravenous contrast for imaging due to a severe allergy. Although biopsy of indeterminate renal lesions can provide valuable diagnostic information, there are inherent risks associated with this procedure. The rare occurrence of tumour seeding should be considered when recommending percutaneous biopsy to a patient with a renal mass.