Sonographically guided renal mass biopsy - Indications and efficacy

Purpose. To review the clinical indications, pathologic results, and succes s rate of all our sonographically guided solid renal mass biopsies over a 5 -year period. Methods. Between 1993 and 1998, 44 consecutive patients under went sonographically guided percutaneous biopsy of a solid renal mass. indi cations included prior history of nonrenal malignancy, metastatic disease o f unknown primary origin, previous contralateral nephrectomy for a renal ce ll neoplasm, a renal transplant mass, suspected renal lymphoma, history of tuberous sclerosis, and poor surgical candidacy. Aspiration biopsies were i nitially performed with 22- to 18-gauge spinal needles, if the initial cyto logic evaluation findings were nondiagnostic, core biopsies were then perfo rmed with 20- to 18-gauge core biopsy guns. Dictated sonographic reports of the biopsies were reviewed to determine the following: indication for biop sy, location and size of the renal mass, needle gauge and type, number of n eedle passes, and complications. Final cytologic and surgical pathologic re cords were reviewed. Results. Thirty-six (82%) of the 44 biopsy specimens w ere diagnostic. Aspirated smears were diagnostic in 24 (67%) of these cases , with the diagnosis made on the basis of cell block alone in an additional 2 (6%). A definitive diagnosis came from core biopsy alone in 10 cases (28 %). The 18-gauge core needle yielded diagnostic results more reliably than the 20-gauge core needle, and a significant correlation was seen between co re biopsy needle size and the rate of diagnostic core samples (P = .017). P athologic diagnoses included renal cell carcinoma (n = 18), lymphoma (n = 4 ), oncocytic neoplasm (n = 4), transitional cell carcinoma (n = 2), angiomy olipoma (n = 1), papillary cortical neoplasm (n = 1), and metastatic carcin oma (n = 6). Complications were seen in 4 (9%) of 44 cases; all were treate d conservatively. Conclusions. For specific clinical indications, sonograph ically guided fine-needle aspiration and core biopsy of a solid renal mass can be performed safely. In many cases, a definitive diagnosis can be made on the basis of fine-needle aspiration alone. However, diagnosis may ultima tely require core biopsy, for which 18-gauge core needles would be more rel iably diagnostic than 20-gauge needles.