Fine Needle Aspiration, Cytomorphological and Mitotic-Karyorrhexis Index (MKI) evaluation
Fine needle aspiration cytology (FNAC) was performed by palpation/image-guidance from various sites and all smears and corresponding cell blocks with immunocytochemistry (if performed) were retrieved and re-evaluated by two expert cytopathologists (RS, MR). Cell blocks from FNA were prepared by plasma thromboplastin technique. These were categorized further as per previously published INPC criteria extended to cytopathology as undifferentiated, poorly differentiated, differentiating neuroblastoma or ganglioneuroblastoma.16 Mitotic-karyorrhexis index (MKI) assessment was performed on well spread H&E-stained smears and their corresponding cell blocks using digital image visual assessment (DIVA).17