1/23, tuberculosis 1/23), and a histiocytosis was found in 1/23].MRI findings revealed 15 patients with diffuse lesions vs 8 focal lesions respectively and 21 patients with enhancing lesions vs 2 patients with nonenhancing brainstem lesions.CONCLUSION: Despite its retrospective nature, our study underlines the risk of misdiagnosis and therapeutic mistakes in the evaluation of infiltrating mass suggesting brainstem glioma.It illustrates the need to promote a more systematic "check-list" based approach of brainstem lesions, including biopsies when needed, as recently shown in the pediatric population. P07.