Tuberous sclerosis Complex (TSC)

Diagnosis
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  • TSC is an autosomal dominant, multisystem disease characterized by hamartomas in multiple organs
  • The classic triad of symptoms (seizures, mental retardation, and adenoma sebaceum) is seen in less than 30% of cases
  • Seizures develop in the majority of patients
  • A definitive diagnosis includes either 2 major features or 1 major and 2 minor features from a list of skin, intracranial, retinal, cardiac, renal, rectal, bone, dental, lymphatic, and gingival features
  • In 90% of patients with TSC, MRI shows rounded, benign lesions (subependymal nodules) along the walls of the lateral ventricles, commonly near the foramen of Monro; the nodules are isointense to mature white matter, can enhance with contrast, and often calcify
  • Another common feature of TSC is multiple epileptogenic cortical/subcortical hamartomas (or tubers), which manifest most commonly in the frontal lobes as expanded gyri; they appear as low signal areas on T1-weighted images and high signal areas on T2-weighted and FLAIR images
  • Subependymal nodules can degenerate into subependymal giant cell astrocytomas (SEGAs) in up to 15% of patients with TSC; they are most commonly seen near the foramen of Monro, often have cystic and solid components that partially enhance, and can grow large enough to cause ventricular obstruction and hydrocephalus
  • The critical imaging finding that differentiates SEGAs from subependymal nodules is that SEGAs tend to enlarge; also, SEGAs enhance and most subependymal nodules do not
  • Hyperintense linear or curvilinear streaks extending from the ventricle to the cortex on T2-weighted images are thought to represent “migration lines” or bands of hypomyelinated disordered cells
  • Tubers often calcify, which is best appreciated on CT scans
  1. Kalantari B, Salamon N. Neuroimaging of tuberous sclerosis: spectrum of pathologic findings and frontiers in imaging. AJR 2008; 190(5):304-309
  2. DiPaolo D, Zimmerman RA. Solitary cortical tubers. Am J Neuroradiol 1995; 16:1360-1364