Purpose: In some cases of uncertain lesions in the kidney it would be helpful to perform biopsies for preoperative histopathological evaluation. In this study we evaluated the accuracy of and the impact on tumor management of core biopsy for histopathological evaluation of small solid renal masses.
Materials and methods: After radical or partial nephrectomy 250 renal tumor biopsies were performed in 50 patients. All biopsies were performed by 1 urologist after preparation of the kidney ex situ on back table visually guided. Formalin fixed paraffin embedded biopsies were evaluated by 1 pathologist.
Results: In 49 of 50 cases (98%) we could define the malignant behavior of the tumor when performing 1 central and 4 peripheral biopsies of each tumor. In 85.2% the grading was correctly defined. A benign lesion was revealed in 4 cases (8%, all oncocytoma). In renal tumors 4 cm or smaller in diameter the accuracy of 1 central and 1 peripheral biopsy each regarding definition of tumor origin, tumor grading and cell type/growth pattern was 96% and 95.5%, 84% and 84.4%, and 87.5% and 89.5%, respectively. In renal tumors more than 4 cm in diameter the accuracy was 100% and 98.1%, 85% and 94.3%, and 71.4% and 88.7%, respectively.
Conclusions: Core biopsy of renal lesions is accurate enough for histopathological evaluation and determination of therapeutic procedure. Additionally, biopsy could be used for identifying benign renal lesion for observation.