[Classical pathology and basic concepts of the current WHO classification (5th edition) of central nervous system...

Considerable changes were introduced into the 5th World Health Organization (WHO) classification of central nervous system (CNS) tumors, published in 2021, including new entities, a clearer classification of previous categories, correlating better with clinical behavior and changes in nomenclature. The number of definitions based on molecular features in addition to histopathology continued to increase. Here, we highlight the basic principles of the 5th CNS WHO classification and discuss glial, glioneuronal, neuronal, choroid plexus, embryonal and pineal tumors, as well as meningiomas in more details. We pay special attention to new entities as well as altered criteria and designations. Our primary goal is to present the "classical" pathological aspects, but the inseparable molecular pathological features are also briefly discussed, to the absolutely necessary extent for comprehension. We aim to provide a guideline to understand the modern classification of CNS tumors for practitioners of neuro-oncology and neuropathology.