Two cases of neuroblastoma comprising two distinct clones

We report two cases of high-risk metastatic neuroblastoma, comprising two biologically distinct components in the adrenal primary tumor, which showed clear differences not only histologically but also in MYCN amplification and HA-RAS/TRKA immunoreactivity (Case 1), anaplastic lymphoma kinase (ALK) immunoreactivity (Case 2). These two cases with multiple separated components were similar to cases classified as ganglioneuroblastoma, nodular subtype (GNBn), in terms of composite tumor. Comparable to the GNBn category, the prognosis of the patients described here may depend on the components with unfavorable histology according to International Neuroblastoma Pathology Classification. Further analyses of such composite neuroblastoma cases are important for assessing disease prognosis.