INTRODUCTION: Tuberous sclerosis complex (TSC) is one of the most frequent 
neurocutaneous disorders. Cortical tubers are the most common pathological 
changes in TSC and they are directly related to the disease's main clinical 
manifestations: seizures, mental retardation, and autistic behaviour.
OBJECTIVE: The aim of this study is to establish a correlation between tuber 
size and the severity of clinical features in TSC.
MATERIAL AND METHODS: We performed a retrospective study of the clinical and 
imaging findings from 45 TSC patients (22 females and 23 males) and compared the 
clinical features with the location, size, and number of the cortical tubers in 
each patient.
RESULTS: Four patients had voluminous tubers located in 1 or both cerebral 
hemispheres. All of these patients had intractable seizures and severe mental 
retardation; 3 of these cases also presented with autistic behaviour, despite 
tubers having been resected in all 4 patients. Thirteen patients had tubers of 
large-to-average size, and all patients in this group showed intractable 
seizures and mental retardation. Nine patients who had experienced infantile 
spasms during the first year of life presented autistic behaviour. Multiple 
tubers of small to average size were found in 28 patients. In general, this 
group had seizures that responded well to antiepileptic drugs and a low 
prevalence of autism. In 3 patients who all presented good seizure control and 
normal intelligence, single cortical/subcortical tubers were located in the 
frontal or occipital lobes. Of the total of 45 patients, 13 had cerebellar as 
well as cerebral tubers; these were generally present in cases with more severe 
clinical features.
CONCLUSIONS: Although large tubers are less common than small to medium-sized 
ones, they are much more likely to be accompanied by severe clinical symptoms 
(seizures, mental retardation and autistic behaviour), even when the smaller 
tubers are quite numerous.