Central nervous system germ cell tumor, an archetypal AYA tumor and a model for pediatric and neuro-oncology collaboration, review from the EURACAN domain 10 group

Abstract

Simple Summary: Adolescents and young adults (AYA) with cancer often fall through gaps between children’s and adults’ cancer services. They are consequently under-represented in clinical trials, and their survival is often inferior to that of children or adults with the same tumor type; in this paper, we use the example of central nervous system germ cell tumors (CNS-GCT), as a model of AYA tumor to illustrate this challenge. We describe how we have built bridges between pediatric and adult oncology, how this can apply to other types of brain tumors, and discuss ways to promote cancer care in the AYA population.Adolescents and young adults (AYA) with cancer are under-represented in clinical trials and have thus not benefited from the same improvement in outcomes as either younger or older patients. Central nervous system germ cell tumors (CNS-GCT) represent an ideal model of AYA tumor as their incidence peaks during adolescence and young adulthood. Since the early 90’s, SIOP (International Society of Pediatric Oncology) has launched two successive European trials: SIOP CNS-GCT96 (January 1996 to December 2005) and SIOP CNS-GCTII protocols (October 2011 to July 2018), for CNS-GCTs. With the removal of the upper age limit in the SIOP CNS-GCTII trial, and closer collaboration between pediatric and adult oncologists within AYA multidisciplinary tumor boards, the proportion of adults enrolled in France has dramatically increased over time. The current article will use the example of CNS-GCT to illustrate how to build a bridge between pediatric and adult oncology, how this can apply to other types of brain tumors, and how to promote cancer care in the AYA population.

Large Immature Intracranial Teratoma in an Infant: A Case Report

“…Approximately 90% of these tumors contain the three layers of germ cells (ectoderm, mesoderm, and endoderm) [ 1 , 6 ]. Intracranial teratomas are classified according to the histological variant: (i) mature teratoma containing well-differentiated tissue with the three germ layers, (ii) immature teratoma containing a population of cells that retain embryonic characteristics and tissues with more primitive components derived from all or some of the three germ layers, and (iii) teratoma with somatic malignancy is the malignant transformation of a teratomatous component (mature or immature) into a non-germ cell malignancy (rhabdomyosarcoma type) [ 3 , 7 , 8 ]. In the reported case, the histological study showed elements of the three germ cell layers (ectoderm, mesoderm, and endoderm) represented by mature elements (cartilage, squamous epithelium, and mucinous glandular epithelium) and immature elements (primitive neuroepithelium), suggesting a diagnosis of immature teratoma, which was confirmed by immunohistochemistry.…”

Bifocal germ cell tumor of pineal germinoma and neurohypophyseal embryonal carcinoma: illustrative case

“… 5 , 6 When CNS GCTs are detected simultaneously in the neurohypophysis and pineal region, they are termed bifocal GCTs, which account for 5.8% to 19.7% of all CNS GCTs. 5 , 7 , 8 Bifocal GCTs, histologically predominantly comprised of germinoma in both the neurohypophyseal and pineal regions, have not exhibited any reported cases with varying histological types between these two regions. 8 , 9 In this report, we present a rare case of a bifocal GCT, in which the pineal region was a germinoma, falling into the category of good prognosis.…”

“…3,4 CNS GCTs occur most frequently in the pineal region (53%-68%), followed by neurohypophysis (19%-37%) and basal ganglia (5%-10%). 5,6 When CNS GCTs are detected simultaneously in the neurohypophysis and pineal region, they are termed bifocal GCTs, which account for 5.8% to 19.7% of all CNS GCTs. 5,7,8 Bifocal GCTs, histologically predominantly comprised of germinoma in both the neurohypophyseal and pineal regions, have not exhibited any reported cases with varying histological types between these two regions.…”