# Simultaneous occurrence of bilateral retroperitoneal neuroblastoma and bifocal malignant mixed germ cell tumor in a pediatric patient with 16p11.2 microdeletion syndrome: a case report

## TL;DR

A 14-year-old boy with a genetic deletion had two rare tumors in his brain and abdomen, marking the first known case of this combination.

## Contribution

This is the first documented case of co-occurring bilateral intracranial germ cell tumors and retroperitoneal neuroblastoma in a patient with 16p11.2 microdeletion syndrome.

## Key findings

- The patient had bilateral retroperitoneal ganglioneuroblastoma and intracranial mixed germ cell tumors.
- Whole-exome sequencing revealed a 16p11.2 microdeletion and an ALK gene variant (p.Arg1275Gln).
- This case highlights a novel association between neuroblastoma, germ cell tumors, and 16p11.2 deletion syndrome.

## Abstract

Central nervous system germ cell tumors are rare intracranial neoplasms that predominantly occur in pediatric populations and exhibit characteristics similar to those of gonadal and extragonadal germ cell tumors. Neuroblastoma (NB) represents the most common type of extracranial solid tumor in children, typically arising in tissues with sympathetic innervation. We present a case involving a 14-year-old male patient diagnosed with bilateral intracranial mixed germ cell tumors and concurrent bilateral retroperitoneal ganglioneuroblastoma. To the best of our knowledge, this is the first documented instance of the co-occurrence of these two distinct neoplastic entities. Additionally, Whole-exome sequencing (WES) of the blood sample identified a chromosomal deletion consistent with the 16p11.2 microdeletion syndrome. Furthermore, a heterozygous missense variant in the ALK gene (p. Arg1275Gln) was identified.