A subtle case of tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is known to cause severe intractable epilepsy and mental retardation; however, diagnosis can be delayed in milder cases. We report a 26-year-old right-handed female patient who started having convulsions at age 7 days. She had several focal seizures per year that were intractable to treatment with carbamazepine or phenytoin. Her two sisters had several episodes of suspected epileptic seizures but had no symptoms related to TSC. Seizure semiology of the patient comprised of visual hallucination, loss of consciousness, and convulsive movements predominantly on the right. Physical examination revealed several small scattered angiofibromas over the nose that were histologically determined by skin biopsy. Hypomelanotic macules, shagreen patches, or periungual fibromas were not seen. Neurological examination showed mental retardation (MMSE: 23/30, WAIS-III: VIQ63, PIQ59, FIQ58) and decreased vibration sensation in both legs. Interictal EEG showed slow waves and epileptiform discharges broadly over the anterior quadrants bilaterally. Brain imaging showed multiple cortical tubers and malformation of cortical development but no subependymal nodules. Interictal IMP-SPECT showed hypoperfusion in the left frontal lobe. Cardiac rhabdomyoma was not noticed by cardiac echography. Truncal CT showed sclerosis of the bilateral lumbosacral joints. There was no abnormality in the lung, major arteries, liver, or kidneys. No hamartomas or retinal achromic patches were noticed by ophthalmologic evaluation. Administration of lamotrigine was effective for her seizures. This patient fulfilled two major features of diagnostic criteria for TSC and was diagnosed as definite TSC. Patients with mental retardation and epilepsy should be carefully evaluated for the possible diagnosis of TSC.