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A Case of Solitary Subependymal Giant Cell Astrocytoma

2005; Elsevier BV; Volume: 7; Issue: 4 Linguagem: Inglês

10.1016/s1525-1578(10)60586-7

1943-7811

Tomotsugu Ichikawa, Akiko Wakisaka, Shigeru Daido, Soichiro Takao, Takashi Tamiya, Isao Date, Shoichi Koizumi, Yo Niida,

Histiocytic Disorders and Treatments

Subependymal giant cell astrocytoma (SEGA) is a unique brain tumor arising in tuberous sclerosis complex (TSC) , an autosomal dominant inheritedphacomatosis.There are several case reports of solitary SEGA without any other manifestations of TSC.Usually these cases are thought to be forme fruste of TSC due to somatic mosaicism.However , no previous reports have used molecular methodology to fully investigate mutations in TSC genes or the possibility of somatic mosaicism.Here , we report a 20-year-old woman with a brain tumor.Pathological diagnosis was consistent with SEGA , but comprehensive clinical screening found no other lesions indicative of TSC.Molecular analysis of the tumor revealed loss of heterozygosity and allelic mutation (5228G>A , R1743Q) of TSC2.To detect the small fraction of mosaic mutation in somatic cells , we developed a highly sensitive new method: triplenested polymerase chain reaction-restriction fragment length polymorphism.The identical TSC2 missense mutation was not detected in any other tissues from the same patient , including peripheral blood , buccal mucosa , urinary sediment , nail , and hair.According to these results , this patient should be considered as having SEGA that developed from two somatic hit mutations in TSC2 , rather than being a TSC2 patient with a very small fraction of somatic mosaicism.(J Mol Diagn 2005, 7:544 -549) Subependymal giant cell astrocytoma (SEGA) is a unique brain tumor that usually accompanies tuberous sclerosis complex (TSC), an autosomal dominant hereditary phacomatosis.Patients with TSC develop multiple hamartomas, mainly in the brain, heart, kidneys, eyes, and skin. 1,26][7][8] Clinical expression of TSC is widely different in each case.Mosaicism is relatively common and well documented in TSC, because up to 10% of patients have somatic and/or gonadal mosaicism. 9 -12 Because SEGAs are characteristic lesions of TSC and were once even considered as pathognomonic, patients with isolated SEGA without any other TSC manifestations are usually considered as a forme fruste of TSC with somatic mosaicism.][15][16][17][18] Here, we report a 20-year-old woman with isolated SEGA and no other clinical manifestations of TSC.We performed comprehensive molecular analysis of the surgically removed SEGA for both LOH and point mutations in the TSC1 and TSC2 genes.We also examined any available tissues throughout the body from the same patient, including peripheral leukocytes (two separate collections in a two year interval), urine, buccal mucosa, hair, and nail, to determine somatic mosaicism. Materials and Methods Case ReportA 20-year-old previously healthy woman presented with sudden onset of headache and vomiting.Brain MRI re-