Original Article Adequacy and Accuracy of Core Biopsy in Children: A Radiologic/Pathologic Correlation Study Lauren N Parsons 1 , Nghia Vo 2 , David C Moe 2 , and Jason A Jarzembowski 1 Abstract Core biopsy (CB) is increasingly popular for assessing solid lesions in children. To date, pediatric literature is limited regarding factors contributing to diagnostically inadequate or inaccurate CB. Therefore, we retrospectively examined radiologic/ pathologic factors associated with adequacy/accuracy of CB in pediatric patients. A search of the surgical pathology database for CB between January 2007 and December 2014 yielded 134 CB from 99 patients. Age, sex, anatomic site of lesion, CB diagnosis, and final diagnosis were acquired from the electronic medical record. Image guidance modality, lesion size, and CB sampling device were obtained from radiology records. CB hematoxylin and eosin slides were reviewed for fragmentation, percentage of fibrosis, and percentage of necrosis. Overall, CB length was measured using cellSens software and a DP71 camera. Groups were compared using 2-sided homoscedastic Student’s t tests; 87.3% (117/134) CB were diagnostic; final diagnosis was available for 105 cases, with a concordance rate of 80.0% (84/105). Image guidance modality, lesion site (extremity vs nonextremity), and CB needle gauge did not significantly differ between diagnostic versus nondiagnostic CB or concordant versus discordant CB. Diagnostic CB had less necrosis and fibrosis than did nondiagnostic CBs (6.8% vs 29.7%, P ¼.0002 and 10.3% vs 29.1%, P ¼.0006). Nondiagnostic and discordant CB were more likely to be from bony lesions than soft tissue (P ¼.01 and P ¼.0248). CB is valuable for diagnosing solid lesions in children, with good overall diagnostic rates regardless of lesion size, location, or imaging modality used for biopsy. Nondiagnostic and discordant CB were more often obtained from bony lesions; sampling via open biopsy may be more useful in that setting. Nondiagnostic and discordant CB have more necrosis and fibrosis, suggesting that on-site evaluation of CB tissue viability—for example, by touch imprint or fine needle aspiration—may be useful in further enhancing CB utility. Keywords Bone tumors, core biopsy, Pediatric pathology, soft tissue tumors, Surgical pathology, tumors Introduction Cancer is the leading cause of disease-related death among children and adolescents in the United States, with an incidence of around 17 cases per 100 000 chil- dren. 1 A wide variety of extracranial solid tumors occur in children, and there are many tumor-specific treatment protocols available to pediatric patients, making diagnos- tic accuracy of paramount importance. Tissue biopsies play an essential role in treating these patients, as ade- quate quantities of viable tissue are needed for histologic evaluation and ancillary testing in order to render an accurate diagnosis, detect potential therapeutic targets, and identify markers of prognostic significance. Open biopsy has been the traditional ‘‘gold standard’’ with respect to obtaining tissue in pediatric patients with a suspicion for, or history of, cancer. However, open biopsies are not always feasible. Some patients, for exam- ple, are clinically unstable at the time of presentation and therefore cannot tolerate an invasive surgical procedure. Furthermore, open biopsies can be associated with sig- nificant cost—as they require an operating room and the associated staff for the surgery and anesthesia and often a 1 Department of Pathology, Children’s Hospital of Wisconsin and Medical College of Wisconsin, Milwaukee, Wisconsin 2 Department of Radiology, Children’s Hospital of Wisconsin and Medical College of Wisconsin, Milwaukee, Wisconsin Corresponding Author: Lauren N Parsons, Children’s Hospital of Wisconsin, 9000 W. Wisconsin Avenue, Milwaukee, WI 53226, USA. Email: lparsons@mcw.edu Pediatric and Developmental Pathology 1–5 ! 2018, Society for Pediatric Pathology All rights reserved. Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1093526618809862 journals.sagepub.com/home/pdp