Pediatric core needle biopsy: strengths and limitations in evaluation of masses.

Needle core biopsies (NCB) are widely used in adults but are less often used for the evaluation of pediatric tumors. To determine the diagnostic utility of NCB for pediatric tumors, we performed a retrospective analysis. Fifty NCB of masses from 1992 to 1998, subsequent pathologic specimens, and medical records were reviewed. All patients were less than 21 years of age. Of the NCB 78% (39/50) were diagnostic of a neoplasm, 8% (4/50) were nondiagnostic in cases where a tumor was subsequently diagnosed, and 14% (7/50) revealed inflammatory or reactive lesions, with no subsequent diagnosis of a neoplasm according to medical record review. In cases in which a neoplasm was present, NCB was diagnostic in 91% (39/43). For cases in which there was a previous diagnosis of a tumor, 100% (9/9) of NCB were diagnostic of a recurrence or metastasis. In cases of NCB for primary tumor diagnosis, 88% (30/34) were diagnostic. The most common problems encountered were related to specimen adequacy, such as insufficient tissue, crush artifact, and tumor necrosis. Tumor diagnoses were as follows: primitive neuroectodermal tumor (PNET)/Ewing sarcoma (12), malignant lymphoma/Hodgkin's disease (8), rhabdomyosarcoma (4), germ cell tumor (3), Wilms' tumor (3), neuroblastoma (1), sarcoma, not otherwise specified (4), and other neoplasms (8). There were no complications of the procedure. NCB of pediatric tumors is an effective diagnostic tool and can be used to obtain diagnostic material quickly and safely. NCB was diagnostic in 90% of cases in this series. When NCB provide sufficient material for immunohistochemical, cytogenetic, flow cytometric, and other ancillary studies, the diagnostic efficacy is enhanced. The major limitations in this series were related to sampling problems and specimen adequacy for comprehensive pathologic evaluation.