[948] Renal Lymph Nodes for Tumor Staging: Appraisal of 861 Adult Nephrectomies with Microscopic Examination of Hilar Fat

Vikas Mehta, Jodi J Speiser, Kumaran M Mudaliar, Maria M Picken. Loyola Univ Med Ctr, Maywood

Background: The role of lymphadenectomy in the management of renal cell carcinoma (RCC) is emerging. While sentinel lymph node (LN) detection is the standard of practice in several cancers, mapping of sentinel LNs has not been utilized in the management of RCC. Studies in porcine models have shown that lymphatic drainage is not uniform. Thus, sampling of LNs during nephrectomy for malignancy is an open issue. Although gross examination of hilar tissue to assess the nodal status is performed routinely, it is not known whether this approach is adequate. Our aim was to evaluate the LN status in nephrectomy specimens.
Design: All radical nephrectomies performed over a 10-yr period were reviewed, with particular attention paid to the identification and number of hilar and other LNs and their tumor involvement. As per protocol, the entire hilar tissue was submitted for histology. If hilar LNs were grossly visible, they were submitted separately by the surgeon or by the pathologist. We also reviewed cases with regional lymphadenectomy. The LN metastases were correlated with the grade & stage of tumor.
Results: Among 861 nephrectomies, including several cytoreductive procedures, in 226 cases 1924 LNs were recovered (avg.8.5 LNs/kidney). 1-22 hilar LNs were identified in 88 cases (40%); of which LNs were grossly seen in 37 cases (83 LNs). Metastases were detected in 32/37 cases with enlarged LNs (67/83 LNs=80%). All of these cases had a higher tumor stage [pT2 x 3; pT3 x 7; pT4 x 5]. The Fuhrman's nuclear grade was II/IV (6 cases), III/IV (20 cases) and IV/IV (6 cases). 55 (25%) nephrectomies with LN yield, showed microscopic hilar LNs (187). All of these LNs were negative for metastases. 99 (43%) of patients had regional lymphadenectomy (gross 853 and microscopic 611: periaortic, paracaval, interaortocaval, common iliac and external iliac. The number of identified LN ranged from 1-45. In 39/99 cases (39%) there were metastases (20% of 853 gross LNs). All of these cases had a higher tumor stage [pT2 x 6; pT3 x 27; pT4 x 6]. The Fuhrman's nuclear grade was II/IV (6 cases), III/IV (24 cases) & IV/IV (9 cases). Cases with negative LN were pT1a(x9), pT1b(x14), pT2(x23), pT3(x12), pT4 (x2).
Conclusions: Microscopic hilar LNs, seen in 25% of cases were all benign, while grossly visible hilar LNs were positive in 80%. LN positivity correlated with tumor stage but not grade. Thus, searching for occult LNs is not practical. In patients who are not at high risk for LN metastases and do not have grossly visible LNs at the time of surgery, regional lymphadenectomy and its associated morbidity may be avoided.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 127, Monday Morning

 

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