Prospective evaluation of fine needle aspiration of small, solid renal masses: accuracy and morbidity

To determine the accuracy and clinical utility of fine needle aspiration (FNA) of small, solid renal masses.

A total of 25 patients with small (less than 5.0 cm), solid, clinically localized renal masses were prospectively identified and evaluated with computed tomography guided FNA with analysis for presence of malignant cells and determination of nuclear grade. The final pathologic findings were used for comparison in each case. All patients had renal cell carcinoma and were managed with radical or partial nephrectomy; 3 had low-grade lesions (Fuhrman's grade 1/4), 2 had high-grade lesions (Fuhrman's grade 4/4), and all other patients had intermediate-grade lesions (Fuhrman's grade 2/4 or 3/4) on final histopathologic assessment.

Overall, 10 aspirations yielded diagnostic malignant cells, and 9 were read as rare as rare atypical cells suspicious for malignancy. The remainder were negative (n = 6). Correlation with final nuclear grade was observed in eight instances and discordance in two instances. Subcapsular hematomas were observed at the time of surgery in 10 patients, but in no instance was the operation adversely affected.

The diagnostic yield of FNA of small, solid renal masses appears to be too low to justify the potential morbidity of the procedure.