Presentation Authors: Philip Macklin, Mark Sullivan*, Charles Tapping, David Cranston, Guy Webster, Ian Roberts, Clare Verrill, Lisa Browning, Oxford, United Kingdom
Introduction: The role of percutaneous renal tumour biopsy (RTB) in the management of radiological indeterminate renal masses is long established. Patients with small renal masses with biopsy proven renal cell cancer (RCC) may be offered active surveillance, ablation or partial nephrectomy and RTB can provide diagnostic tissue for patients with metastatic disease who may be candidates for systemic therapy. Current guidelines suggest that tumour seeding of the tract of RTB is anecdotal and a coaxial technique should be used to avoid potential seeding of the biopsy tract..
Methods: Between January 2014 and September 2017 we have performed 585 renal tumour resections within our tertiary referral institution and 196 RTB have been performed. The renal tumour biopsy tract was carefully examined for macroscopically in the resection specimen and where found targeted when taking the histological blocks for microscopic assessment.
Results: We report seven cases in this series in whom RTB tract seeding has been identified on histological examination of the subsequent resection specimen; 6 papillary RCC's and 1 clear cell RCC. In six of these cases the presence of tumour in the perinephric fat upstaged the tumour to T3a which would otherwise have been TNM 8th Ed stage pT1. Two of the patients have subsequently developed local tumour recurrence within the renal bed at a site consistent with the biopsy tract
Conclusions: In the modern literature, the first published case of seeding of the tract of a RTB by RCC, which was histologically evident, was published in 2013. There have since been four further case reports of RTB tract seeding evident on histology, one of whom has had documented local recurrence, with three further reported cases of suspected RTB tract seeding and local recurrence. We hereby present the largest series of patients who have histologically evidence of RTB tract seeding and which is most commonly associated with papillary RCC. The RTB site can be identified macroscopically in the majority of renal tumour resection specimens and should be targeted when taking blocks in order to exclude the presence of biopsy tract seeding. Patients should be informed of a real though small risk of tract seeding and upstaging following RTB.