Tehran University of Medical Sciences Current Journal of Neurology 2717-011X 11 1 2012 03 15 30 33 Marjan Asadollahi Loghman Hospital, Department of Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Nasrin Shayanfar Rasoul-Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran Bibiseyedeh Rezaiyan Loghman Hospital, Department of Neurology, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mehrdad Hasibi Amir-Alam Hospital, Tehran University of Medical Sciences, Tehran, Iran 2015 10 17 Medulloblastoma is one of the most common primary tumors of the central nervous system of children but it is uncommon in adult age. We report a case of young male presented with a history of generalized headache that was found to have medulloblastoma with diffuse leptomeningeal involvement without prominent mass lesion. To our knowledge, our patient is the second reported case of medulloblastoma in adults identified with primary leptomeningeal involvement without a prominent mass lesion. The clinical, radiological and pathologic features of this entity are described. https://ijnl.tums.ac.ir/index.php/ijnl/article/view/834 https://ijnl.tums.ac.ir/index.php/ijnl/article/download/834/99