INTRODUCTION
Peripheral neuroblastic tumors (pNTs), which comprise neuroblastoma
(NB), ganglioneuroblastoma, and ganglioneuroma, have well-established
prognostic factors such as age at diagnosis, clinical stage
(International Neuroblastoma Staging System), MYCN status,
chromosomal abnormalities (Chromosome 1p and 11q deletions), DNA ploidy
pattern, and histopathology classification (International Neuroblastoma
Pathology Classification; INPC). Based on these factors, NB cases can be
classified into four categories: very low-risk, low-risk,
intermediate-risk, or high-risk; which will in turn determine the
treatment protocol applied.1-5MYCN -amplification (MYCN -A) demonstrate is a common
histologic characteristic of NB, whereas undifferentiated/poorly
differentiated NB subtype harbor a high mitosis-karyorrhexis index
(MKI), which is considered unfavorable histology (UH) in INPC
classification.
According to INPC, the MYCN -A is rarely found in a tumor showing
favorable histology (FH: pathologically good prognosis group). Tumors
within the MYCN -A and FH group account for only 1.1% of all NB
cases, and their treatment remains controversial. Suganuma et al.
reported a case of MYCN -A+FH genotype–phenotype discordant and
analyzed its histopathological nature. Their analysis revealed that such
discordant cases could be divided into good or poor prognosis groups
based on the nuclear morphology and the presence of N-myc expression,
resulting in subclassification of ”conventional” (“salt and pepper”
nucleoli) and ”Bull’s eye” (prominent nucleoli) tumors.
Herein, we present two genotype–phenotype discordant NB cases, which
further support the relevance of histopathology, along with N-myc
expression analysis, as important factors for selecting an appropriate
treatment for pNTs.