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Neuroradiology Case of the Week

Case 101

Peter Takeyama, MD and PL Westesson, MD, PhD, DDS

Clinical Presentation: A 9-year-old male with a history of tuberous sclerosis diagnosed at the age of six months when he initially presented with infantile spasms. Patient continues to have daily seizures and is developmentally delayed as well. Serial imaging studies of the head have been performed to follow a cystic lesion in the left frontal lobe. This current study is status post-biopsy.

Radiological Findings: Cystic lesion in the left frontal lobe (large arrow) with pneumocephalus and blood in the cystic lesion consistent with recent biopsy. Slight edema around this lesion with effacement of the left lateral ventricle.
     Calcified cortical/subcortical tubers over bilateral parietal lobes. There are calcified subependymal nodules adjacent to the ventricles (arrowhead). Calcification of the right cerebellar parenchyma is also noted (thin arrow).

Pathology: Biopsy specimen from the left frontal lobe cystic lesion was consistent with pilocytic astrocytoma.

Diagnosis: Tuberous sclerosis and pilocytic astrocytoma

Discussion: Tuberous sclerosis is one of the phakomatoses in which hamartomas are formed from abnormal cellular differentiation, proliferation and migration. The organs that it affects include the brain (cortical/subcortical tubers, subependymal nodules, and giant cell astrocytomas), kidney (angiomyolipomas, cysts), skin (ash leaf spots, shagreen patches, angiofibromas, periungual fibromas), eye (retinal hamartomas), heart (rhabdomyomas), lungs (LAM) and other organs.
     Tuberous sclerosis is associated with giant cell astrocytomas. However, an association with pilocytic astrocytoma is not known. Tassel et al. [2] noted cyst-like lesions in 44% of 18 tuberous sclerosis patients they studied. They concluded, however, that it was not clear whether the cystic lesions were due to degeneration of dysplastic tissue or an entirely unrelated process.

References:

1. Sparagana SP. Roach ES. Tuberous sclerosis complex. Current Opinion in Neurology. 13(2):115-9, 2000 Apr.
2. Van Tassel P. Cure JK. Holden KR. Cystlike white matter lesions in tuberous sclerosis. American Journal of Neuroradiology. 18(7):1367-73, 1997 Aug.