Intravenous Dissection, the Optimum Strategy for Staging of Renal Cell Carcinoma
SM Bonsib, A Bhalodia. Louisiana State University Helath Science Center, Shreveport, LA
Background: The most common avenue of extra-renal extension for clear cell (CC) renal cell carcinoma (RCC) is via renal sinus veins (RSV). Opening a nephrectomy specimen through its venous system may permit gross demonstration of the earliest phase of this process.
Design: Thirty-six radical nephrectomy specimens containing 38 RCCs (27 CC, 7 papillary, 2 chromophobe, 2 other) were examined for RSV involvement. Intravascular fixation was employed for 13/36 cases consisting of intraarterial and intravenous formalin injection, followed by intravenous formalin perfusion under hydrostatic pressure for 4-16 hrs. For all specimens, 2-3 probes were placed in RSV and the specimens bi-valved along the probes.
Results: Intravenous perfusion permitted optimum visualization of RSV and intravenous tumor by fixing the veins in an open position.
Sinus intravenous extension was observed in 21/38 RCC; all 21 were CC.
13 of 21 involved RSV, not the main renal vein (MRV); 10 also involved the peripheral perinephric fat. 3/21 cases had early RSV involvement with 2-3 mm of tumor within a large vein adjacent to the primary tumor. Retrograde cortical venous spread occurred in 7/21 cases with RSV involvement. In 11/21 cases with RSV involvement, the sinus fat was not involved. Only 1/38 involved peripheral perinephric fat but not RSV. Metastatic disease was present at nephrectomy in 8/21 cases with RSV involvement; the MRV was negative in 5/8. No case without RSV involvement had metastases at nephrectomy.
Conclusions: Intravenous dissection is easy to perform when obtaining the venous resection margin and makes identification of pT3b disease easy to recognize. RSV involvement is common in CC-RCC and often the only evidence of extra-renal pT3 disease. Failure to perform intravenous dissection may have resulted in staging errors (pT/T2 vs pT3) in 3/36 cases due to limited RSV involvement.
Category: Genitourinary (including renal tumors)
Tuesday, March 23, 2010 9:15 AM
Platform Session: Section A, Tuesday Morning