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Neuroradiology

E1023. Supratentorial Intra- and Extraaxial Neoplasms: Algorithm Approach for Residents

Aluja Jaramillo F1,2,  Mora Salazar J1,2,  Nieto Taborda K1,2,  Tramontini Jens C1,2,  Rivas Rodriguez F.3 1. Fundación Universitaria Sanitas, Bogotá, Colombia; 2. Clínica Universitaria Colombia, Bogotá, Colombia; 3. University of Michigan, Ann Arbor, United States

Address correspondence to F. Aluja Jaramillo (macario171@gmail.com)

Background Information: Primary neoplasms of the CNS are histologically diverse, arising from different tissues (e.g., neuroepithelial or hematopoietic). Most of these neoplasms are neuroepithelial and intraaxial. There are multiple classifications for these entities that may confuse the residents and fellows, so we propose a new algorithm approach based on the 2016 World Health Organization (WHO) classification, which classifies these lesions according to location and imaging characteristics to guide an appropriate diagnosis.

Educational Goals/Teaching Points: The goals of this exhibit are to recognize the different types of intraaxial and extraaxial supratentorial tumors based on the novel WHO classification as well as their clinical presentation and treatment. We will describe imaging findings associated with intraaxial and extraaxial supratentorial tumors on CT and MRI. We will review the key elements of the imaging diagnosis, focusing on lesion characteristics, localization, associated findings, and other information needed for an adequate diagnosis. We propose a simple algorithm for the classification of intraaxial and extraaxial supratentorial tumors based on location and imaging characteristics.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: CNS neoplasms may be divided into intraaxial and extraaxial. In this academic exhibit, we focus on those neoplasms that arise in the supratentorial compartment. Intraaxial neoplasms may have a predilection for specific locations in the gray matter (cortical) of the frontal lobe (e.g., oligodendroglioma and anaplastic oligodendroglioma), temporal lobe (e.g., pleomorphic xanthoastrocytoma and dysembryoplastic neuroepithelial tumors), or temporal and parietal (e.g., ganglioglioma). Additional locations include the white matter, frontal and temporal lobe, and corpus callosum (e.g., glioblastoma multiforme and lymphoma) and frontal or temporal lobe (e.g., diffuse astrocytoma [isocitrate dehydrogenase {IDH}-mutant, IDH-wildtype, and not otherwise specified {NOS}] and anaplastic astrocytoma [IDH-mutant, IDH-wildtype, and NOS]). Neoplasms involving the gray and white matter as subcortical involvement are related to metastatic disease. Neoplasms arising on the ventricular system are grouped as intraventricular neoplasms (as they all compromise primary the lateral ventricles), such as choroid plexus papilloma, choroid plexus carcinoma, ependymoma, and intraventricular meningioma. Extraaxial neoplasms such as meningioma (typical, atypical, and malignant), hemangiopericytoma, primary meningeal lymphoma, and mesenchymal meningeal tumors are included as a separate group given their location. Terms as gliomatosis cerebri have been deleted and classified as a different neoplasm to be included as a description of the invasion of some gliomas.

Conclusion: Primary neoplasms of the CNS are diverse and have a wide differential diagnosis. Each one of the CNS neoplasms may have an individual characteristic that has been mentioned. This simple algorithm for the intraaxial and extraaxial supratentorial tumors based on location and imaging characteristics may help and guide the residents and fellows to an appropriate diagnosis.