L-2-Hydroxyglutaric aciduria (LHGA) is a rare autosomal recessively inherited neurodegenerative disorder. It is characterized by psychomotor retardation, progressive ataxia and typical magnetic resonance imaging findings, and presents in early infancy. On the other hand, medulloblastomas are very common solid tumors of childhood and infancy. We present a 3-year-old boy with LHGA who developed a medulloblastoma during the course of the disease. There has been no previous report of the coexistence of medulloblastomas with LHGA. Central nervous system tumors are encountered in children with other metabolic neurodegenerative disorders. The aim of this paper is to focus on the difficulties in the diagnosis and treatment of an intracranial tumor in a child already neurologically impaired due to metabolic neurodegenerative disease. Copyright (C) 2002 S. KargerAG, Basel.