CASE REPORT
Case 1. A 3-month-old female infant presented with left adrenal gland origin NB, stage 4S. Her urine homovanillic acid (HVA) and vanillylmandelic acid (VMA) levels were 6,612 μg/mg Cr (<18 µg/mg Cr) and 3,200 μg/mg Cr (<23 µg/mg Cr). Because the case was complicated with inferior vena cava syndrome, irradiations to the liver (1.5 G/dose, for 3 days) and one cycle of chemotherapy (vincristine and cyclophosphamide) were administered prior to tumor biopsy for avoiding any oncology emergency. The biopsy image of the metastases of the liver after the irradiation showed that the NB was poorly differentiated with intermediate MKI (192/5000). Histology data after chemotherapy led to a classification of conventional NB as per Suganuma classification, which is equivalent to FH of INPC (Fig. 1A). DNA ploidy analysis showed that the tumor was diploid, and real time polymerase chain reaction (RT-PCR) data showed that it harbored 20 copies of MYCN . MYCN -A was also detected by fluorescencein situ hybridization (FISH) (Fig. 1B). Immunohistochemical staining with an anti-N-myc rabbit polyclonal antibody (Proteintech Group, Rosemont, IL, USA) revealed that the tumor was negative for N-myc (Fig. 1C). She received six cycles of chemotherapy (cisplatin, vincristine, cyclophosphamide, and pirarubicin), underwent total resection of the primary tumor and 13-cis-retinoic acid maintenance therapy without autologous stem cell rescue and radiation therapy in the tumor bed. She remained disease-free for the 74 months following tumor resection.
Case 2. A 10-month-old male infant presented with left retroperitoneal NB, stage 2B. Urine HVA and VMA levels were of 168.2 µg/mg Cr and 101.3 μg/mg Cr. The biopsy showed that the NB was poorly differentiated with a low MKI (26/5000), fitting within the FH classification (Fig. 1D). The tumor showed to be a mixture of diploid and hyperdiploid. Moreover, it harbored 5.6 copies of MYCN , which was not considered to beMYCN -A but genetic gain.7 MYCN -A detected by FISH (Fig. 1E) helped interpret the clinical data as a discordance case. The tumor histology showed that the NB was a conventional type as per the Suganuma classification, since N-myc staining was negative (Fig. 1F). He received six cycles of chemotherapy (cisplatin, carboplatin, etoposide, vincristine, cyclophosphamide, and pirarubicin), underwent total resection of the primary tumor and received 13-cis-retinoic acid maintenance therapy without autologous stem cell rescue and radiation therapy. He remained disease-free for the 38 months following the tumor resection.