The New Tumor Predisposition Syndromes with Neuro-Oncological Relevance-A Comprehensive Review for Neuroradiologists.

The 5th edition of the WHO Classification of Tumors of the Central Nervous System (CNS) introduced new additional tumor predisposition syndromes (TPS) that were not included in the 2016 version of the WHO Classification. It is essential for neuroradiologists to be familiar with these novel TPS entities, as accurate imaging interpretation and clinical evaluation often depend on recognising patterns of peripheral and central nervous system findings. Such identification should lead to genetic testing to confirm the suspected TPS diagnosis. Generally, neuroradiological features of brain tumors arising in these TPS are not distinctly different from those observed in sporadic forms of the same tumors. Even in uncommon cases such as meningiomas with aggressive behaviour, often seen in BAP1 syndrome, imaging and clinical evaluations can only suggest TPS; a definite diagnosis cannot be made from phenotype and imaging alone. This review discusses all new TPS in detail and presents their phenotypic spectrum known today. Knowledge of the genetic aspects of each TPS provides additional support to neuroradiologists due to the certainty of the clear distinguishability of TPS. For example, in conditions such as DICER1 syndrome and Fanconi anaemia, the diversity of genetic mutations contributes directly to the broad spectrum of phenotypic manifestations. As a result, genetic knowledge is essential not only for diagnosis but also for appreciating the complexity and heterogeneity of these syndromes in clinical practice. Finally, this discussion includes other TPS that, while not yet classified as distinct entities in the current edition of the WHO Classification of Tumors of the CNS, remain relevant to the field of neuro-oncology.