Purpose: To evaluate the feasibility, accuracy, and clinical role of fine-needle percutaneous biopsy of renal masses, with helical computed tomographic (CT) guidance.
Materials and methods: In 63 patients (mean age, 62 years), 73 biopsies were performed. The median tumor size was 4.0 cm. Tumor biopsy was performed with an 18-gauge needle by using helical CT guidance in an outpatient setting. Two to four cores per tumor were obtained.
Results: Biopsy material was insufficient for analysis in 15 (21%) procedures. The median tumor size of failed or successful biopsies was 3.0 or 4.8 cm, respectively (P =.03). A benign lesion was found at eight biopsies. Two samples were suspicious for renal cell carcinoma (RCC). RCC was found in 38 biopsy samples. The remainder were transitional cell carcinoma, metastasis, lymphoma, or sarcoma. Twenty-six patients underwent nephrectomy. The accuracies of biopsy for histopathologic and Fuhrman nuclear grade evaluation were 89% and 78%, respectively. For tumors of 3.0 cm or smaller or larger than 3.0 cm, 37% (11 of 30) or 9% (four of 43) had failure of biopsy, respectively (P =.006). No substantial morbidity occurred.
Conclusion: Fine-needle biopsy with helical CT guidance is accurate for the histopathologic evaluation of renal masses without morbidity. Indications are renal lesions that do not have the typical radiologic features of RCC, Bosniak category III or IV cystic lesions, and locally advanced or metastatic RCC.