Pretreatment, ultrasound-guided cutting needle biopsies in childhood renaltumors

Background. The current International Society of Paediatric Oncology (SIOP) -10 protocol does not allow pretreatment histological classification of low -stage renal tumors in children for fear of needle tract recurrences. The a ims of this retrospective study were to evaluate the safety, sensitivity, a nd specificity of ultrasound-guided cutting needle biopsies (UCNB) performe d at our institution in pediatric patients with renal tumors. Procedure. Of 28 pediatric patients presenting with a renal tumor between 1988 and 1996, 25 underwent biopsy with the Biopty biopsy instrument (needle diameter 1.2 mm). The preoperative biopsy and nephrectomy slides were reviewed by a SIO P reference pathologist. The patients' hospital records were reviewed and b iopsy complications were noted. Results. At review of the nephrectomy slide s, the diagnoses were: Wilms tumor (16 patients), with anaplasia in one cas e, rhabdoid tumor (2 patients), neuroblastoma (2 patients), mesoblastic nep hroma (2 patients), clear cell sarcoma (1 patient), malignant teratoma (1 p atient), and renal cell carcinoma (i patient). No needle tract recurrence o r other major complication was observed. The only complication was local pa in at the biopsy site, which occurred in 24% (6/25) of the cases. The sensi tivity of UCNB was 76% (19/25); five biopsies did not yield diagnostic mate rial and one was not concordant. All cases of Wilms tumor were correctly di agnosed by UCNB, but only 33% (3/9) of the other tumors. Conclusions. In al l cases of Wilms tumor a correct diagnosis was made. The overall sensitivit y was 76%. UCNB proved to be a safe procedure that was not associated with needle tract recurrence or other serious complications. Med. Pediatr. Oncol . 32:283-288, 1999. (C) 1999 Wiley-Liss, inc.