Intradural dermoid cysts may rupture and subsequent subarachnoid dissemination of lipid droplets has been described before. However, the rupture of a spinal dermoid cyst into the central spinal canal is a rare entity. In this context, dissemination of fat into the intracranial subarachnoid space with local progression is a peculiar finding that, to the best of our knowledge, has not been published so far. We describe the case of a 28-year-old man with a dermoid cyst at the upper lumbar level as part of a complex congenital craniospinal malformation, presenting with new unspecific neurologic symptoms. CT and MRI revealed disseminated intraventricular and subarachnoid lipid droplets intracranially and in the spine not present on previous CT and MRI scans obtained eight years earlier. Thus, repeated rupture of a spinal dermoid cyst with subarachnoid spread and/or secondary proliferation should be suspected.
Keywords: MRI; central spinal canal; dermoid tumour; subarachnoid space.