2.3. Pathological findings of the extirpated specimen
Hematoxylin-eosin staining revealed <50% stroma of Schwann cells and a low mitosis karyorrhexis-index (MKI) (Fig. 2D), and immunohistochemical staining showed positivity for VIP (Fig. 2E). The definitive pathological diagnosis according to the international neuroblastoma pathology classification of the Shimada system [8] was neuroblastoma, differentiating subtype with a low MKI, favorable histology, MYCN not amplified.