Embryonal and pineal tumours

Embryonal and pineal tumours represent a diverse group of central nervous system (CNS) neoplasms. While many of the small round blue cell tumours that make up the embryonal neoplasms share similar histologic qualities, there are several morphologic and cytologic characteristics that are useful in distinguishing different tumour types. Similarly, pineal parenchymal tumours represent clinically diverse tumours, ranging from benign to overtly malignant. The most recent iteration of the World Health Organization Classification of CNS Tumours expanded greatly on the significance of molecular alterations in brain tumour diagnostics. In this article, we summarize the salient cytologic and histologic features of CNS embryonal and pineal tumours, and highlight diagnostically relevant molecular alterations within each tumour type. In the article by Reznicek et al., the authors provide a comprehensive overview of the cytologic, histologic, and molecular features of embryonal tumours and pineal gland tumours of the central nervous system. Integrating high-quality photomicrographs with the most up-to-date knowledge of molecular diagnostics, the article will serve as an invaluable resource for practicing pathologists.