To describe clinical features and neuroimaging findings in the main spectrum of inflammatory and immune-mediated disorders that affect the brainstem.

When finding an inflammatory lesion in the brainstem we face a differential diagnosis. Some autoimmune, paraneoplastic, metabolic and infectious disorders may show similar appearances, making an accurate approach difficult. We review the most common entities providing their epidemiology, pathophysiology, clinical presentation and neuroimaging findings. We emphasize MRI features that help distinguish between them.

Multiple sclerosis (MS) MS is an acquired inflammatory disorder of the Central Nervous System (CNS) that usually starts between adolescence and the sixth decade. Patients that have brainstem lesions show ocular dysmotility, nystagmus, facial sensory loss, trigeminal neuralgia, dysarthria, pyramidal weakness and ataxia. CSF-restricted oligoclonal bands are found in 85% of patients. Neuroimage Diagnosis can be done by MRI if there is evidence of dissemination of lesions in time and space. Lesions are ovoid, well-circumscribed, hyperintense on T2-weighted sequences and fluid-attenuated inversion recovery (FLAIR) sequences....

There is a wide spectrum of inflammatory disorders that can affect the brainstem. The knowledge of their clinical and MRI features can give the radiologist crucial information to reach an accurate diagnosis, making an appropriate treatment possible.

C. García De Andoin Sojo: Nothing to disclose L. Antón: Nothing to disclose I. Alonso Sánchez: Nothing to disclose I. Aza: Nothing to disclose M. d. M. Sarmiento: Nothing to disclose M. Saenz: Nothing to disclose E. Onís: Nothing to disclose M. Sarabia Unibaso: Nothing to disclose J. J. Gómez: Nothing to disclose

Sotoudeh H, Razaei A, Saadatpour Z, Gaddamanugu S, Choudhary G, Shafaat O, Singhal A. Brainstem Encephalitis. The Role of Imaging in Diagnosis. Current Problems in Diagnostic Radiology 2021; 50(6): 946-960. Law LY, Riminton DS, Nguyen M, Barnett MH, Reddel SW, Hardy TA. The spectrum of immune-mediated and inflammatory lesions of the brainstem. Clues to diagnosis. Neurology 2019; 93: 390-405. Lopes L, Rodrigues A, Kok F, da Costa C, Tavares L. Adult Leukodystrophies: A Step-by-Step Diagnostic Approach. Radiographics, 2019. Published Online: Jan 8. Hegde A, Mohan...