The sebaceous nevus syndrome (SNS) is characterized by the presence of a sebaceous nevus and extracutaneous abnormalities, usually involving organs derived from the neuroectoderm. The authors report the case of a 22 year-old patient with a systematized sebaceous nevus on the forehead and scalp and a history of developmental delay and severe seizure disorders. The father of the patient also indicated prior surgery to correct an ocular coloboma and prior removal of a squamous cell epithelioma of the tongue. Firstly described by Gustav Schimmelpenning in 1957, SNS, also known as 'Schimmelpenning-Feuerstein-Mims syndrome', is one of the six different types of epidermal nevus syndromes. In patients with SNS the risk of developing neoplasms is higher than that of the general population. The particularity of our case lies in the late diagnosis. The authors believe that early diagnosis and awareness of the potential presence of neoplasms are important for those involved in the care of patients with SNS.