Radiology Resident Case of the Week
Etiology/Pathophysiology:
Although it's an autosomal dominant disease involving the long arm of chromosome 9, tuberous sclerosis most commonly occurs spontaneously (60%). The incidence is about 1/150-100,000 live births
Pathology:
This disease is a "shotgun blast". It hits the entire body. The intracranial changes are due to "tubers" 1-2 cm in size which can involve cortex and/or subependyma. Microscopically, they exhibit bizarre architecture with surrounding gliosis and fibrillary background. The cells are enlarged multinuclear astrocytes. The lesions have a tendency to calcify.
When there are subependymal and periventricular nodules, "Candle guttering" may be seen (88% calcify) along the lateral ventricles.
Cortical and subcortical tubers are most common in the frontal lobes. The subependymal lesions may degenerate to a Giant Cell Astrocytoma (2-15% of patients). This tumor, although usually benign, can grow large and causes symptoms due to its mass effect. They most commonly occur around the Foramen of Monro, and may lead to obstructive hydrocephalus.
Other organ systems involved include the following:
Miscellaneous:
Imaging:-Intracranial:
Plain film- may see calcifications.
CT- calcifications, tubers, candle guttering, and giant cell astrocytomas (with or without complications).
MR- tubers are well seen on MR with increased T2 signal. The subependymal lesions are demonstrated on T1WI. 31%, 3%, and 12% of the subepenymal, cortical and white matter changes enhance respectively. Giant cell astrocytomas are increased on T2WI with moderate enhancement.
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