Ultrasound-guided core biopsy with on-site cytology-immediate diagnosis in pediatric oncology

Background: Accurate and swift tissue diagnosis is extremely important for the timely initiation of treatment in pediatric oncology. In our department, ultrasound-guided core needle biopsy (US-guided CNB) is used for tissue diagnosis. In 2016, we added on-site cytology, allowing for an immediate primary diagnosis. We retrospectively reviewed our performance in terms of safety and accuracy for CNBs and on-site cytology. Methods: All pediatric biopsies performed in our hospital between February 2016 and December 2020, were included. Patient clinical, procedural and follow-up data were collected. CNB pathology and cytology results were compared to the final pathologic diagnosis. Results: We included 71 patients for which 72 biopsies with on-site touch imprint (TI) cytology were performed; the average latency time to biopsy was 1 day. Altogether, we had 61 tumors, (58 malignant, 3 benign) and 11 other lesions. On-site cytology diagnosed 58 malignant tumors, 3 benign tumors and 11 non-tumor tissues. The cytologist correctly differentiated tumor from inflammation in all cases, and diagnosed the precise tumor type in 57 cases, with an accuracy of 94% for final diagnosis. We had no complications related to the procedure or sedation. Conclusion: US-guided CNB with on-site TI cytology for suspected malignancy in the pediatric population is highly available, safe, and accurate, with real-time diagnosis in most cases. This accelerated diagnostic route has a huge impact on patient care.