[406] Evaluation of Renal Neoplasms by FNA and Core Biopsy: Benefits of a Combined Approach To Sampling during Radiofrequency Ablation as Demonstrated by 215 Consecutive Cases

GE Parks, LA Perkins, AJ Garvin, KR Geisinger. Wake Forest University School of Medicine, Winston-Salem, NC

Background: Radiofrequency ablation (RA) is an acceptable therapy for primary malignancies of the kidney, especially in patients with low stage tumors who may not be good surgical candidates, permitting preservation of renal function. Usually, no pathologic diagnosis of tumor is made prior to therapy. However, at our hospital, pre-RA percutaneous sampling is performed under CT guidance with both fine needle aspiration biopsy (FNAB) and core biopsy (CB).
Design: We report on the complementary roles of these 2 techniques and the advantage of FNAB over CB in a series of 215 consecutive patients undergoing RA for renal neoplasia.
Results: In 88 patients (57%), both specimens were positive for neoplasm. In 13 (9%), both were negative for tumor. In 45 (29%), the FNABs were positive, but the CBs negative. The reverse occurred in 8 patients (5%). When suspicious interpretations by FNAB and CB are added to the calculations, both their complementary nature and the relative higher diagnostic value of FNAB persisted. FNAB positive or suspicious for neoplasm (165 total with concurrent CB), were characterized as renal cell caricnoma (RCC), not otherwise specified (NOS) in 77 cases, RCC clear cell / conventional type in 39, RCC papillary type in 23, neoplasm NOS in 11, RCC with oncocytic features in 5, oncocytoma in 4, angiomyolipoma in 2, and 1 case each of RCC sarcomatoid type, RCC chromophobe type, undifferentiated carcinoma, and metastatic neoplasm. In 14 cases with positive FNABs, the CB allowed a more specific tumor classification. The 8 cases of FNAB considered negative had corresponding CBs that were diagnostic of RCC (6 cases), non-Hodgkin's lymphoma and angiomyolipoma (1 each).
Conclusions: Our findings illustrate the value of the combination of the two biopsy methods for a reliable pretherapy morphologic confirmation of renal neoplasm in that, while FNAB has a relatively greater diagnostic potential and utility for onsite evaluation, the CB provides an additional sample with material for sublassification and additional studies.
Category: Cytopathology

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 53, Wednesday Afternoon