Imaging-guided core biopsy for the diagnosis of malignant tumors in pediatric patients.

Objective: We evaluated the ability of imaging-guided core biopsy to obtain sufficient tissue from pediatric tumors for a definitive diagnosis of malignancy on which treatment could be based.
Materials and Methods: Thirty-four biopsies (biopsies of the abdomen, 32; of the chest, 2) were performed on 34 children at presentation under CT or sonographic guidance using 14-, 18-, or both 14- and 18-gauge needles. A minimum of two tissue cores was obtained. Most biopsies were performed under general anesthesia, permitting other procedures to be performed. The biopsy results were confirmed by subsequent surgical pathology, bone marrow biopsy, biochemical or clinical features, and follow-up examination.
Results: The needle biopsy diagnoses were nephroblastoma (n = 11), neuroblastoma (n = 7), renal cell carcinoma (n = 2), synovial sarcoma (n = 1), non-Hodgkin's lymphoma (n = 2), clear cell sarcoma (n = 1), rhabdoid tumor (n = 1), pulmonary blastoma (n = 2), embryonal rhabdomyosarcoma (n 1), germ cell tumor (n = 1), adrenal carcinoma (n = 1), inflammatory tissue (n = 2), desmoplastic tumor of the mesentery (n = 1), and primitive neuroectodermal tumor (n = 1). In 28 patients, the results were confirmed as correct (22 with surgery and 6 with follow-up examination). Four patients required additional biopsy. In two of these patients, the core biopsy showed inflammatory tissue only, and an open biopsy of a different site was performed; the other two patients did not respond to therapy on the basis of needle biopsy results, and an open biopsy altered the diagnosis. Two patients with widespread disease were excluded because they did not respond to treatment and were too ill to undergo an open biopsy. Only one significant complication was recorded.
Conclusion: Imaging-guided core biopsy is a safe and reliable means of obtaining sufficient tissue to make a confident histologic diagnosis of malignant pediatric tumors in a high percentage of patients.