Case Report

Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report

Volume: 28 Number: 2 August 21, 2026

Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report

Abstract

Subependymal giant cell astrocytoma (SEGA) usually arises near the foramen of Monro in patients with tuberous sclerosis complex (TSC). A 14-year-old boy presented with headache and a 6.2 × 5.8 cm extraventricular, cyst-dominant hemispheric lesion containing a mildly enhancing mural nodule. Microsurgical excision was performed. Histology demonstrated mixed spindle and polygonal epithelioid/ganglioid cells in a fibrillary, microvascular stroma. Tumor cells were positive for glial fibrillary acidic protein (GFAP) and cluster of differentiation 56 (CD56); epithelial membrane antigen (EMA), inhibin, and thyroid transcription factor-1 (TTF-1) were negative, and the Ki-67 labeling index was approximately 1%. No additional major or minor feature of TSC was identified using the 2021 International TSC Consensus criteria. At 12 months, the patient was neurologically intact and headache-free. Germline or tumor TSC1/TSC2 testing and postoperative contrast-enhanced magnetic resonance imaging (MRI) were unavailable. This case highlights the integrated assessment required for pediatric cystic tumors with mural nodules.

Keywords

References

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Details

Primary Language

English

Subjects

Brain and Nerve Surgery (Neurosurgery), Pediatric Genetic Illnesses, Pediatric Hematology and Oncology

Journal Section

Case Report

Publication Date

August 21, 2026

Submission Date

March 7, 2026

Acceptance Date

August 10, 2026

Published in Issue

Year 2026 Volume: 28 Number: 2

APA
Kaya, M., Bakaç, M. Ö., Özdemir, Ç., & Yılmaz, F. (2026). Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report. Duzce Medical Journal, 28(2), 246-251. https://doi.org/10.18678/dtfd.1904928
AMA
1.Kaya M, Bakaç MÖ, Özdemir Ç, Yılmaz F. Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report. Duzce Med J. 2026;28(2):246-251. doi:10.18678/dtfd.1904928
Chicago
Kaya, Mustafa, Muhammed Ömer Bakaç, Çağla Özdemir, and Fahri Yılmaz. 2026. “Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report”. Duzce Medical Journal 28 (2): 246-51. https://doi.org/10.18678/dtfd.1904928.
EndNote
Kaya M, Bakaç MÖ, Özdemir Ç, Yılmaz F (August 1, 2026) Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report. Duzce Medical Journal 28 2 246–251.
IEEE
[1]M. Kaya, M. Ö. Bakaç, Ç. Özdemir, and F. Yılmaz, “Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report”, Duzce Med J, vol. 28, no. 2, pp. 246–251, Aug. 2026, doi: 10.18678/dtfd.1904928.
ISNAD
Kaya, Mustafa - Bakaç, Muhammed Ömer - Özdemir, Çağla - Yılmaz, Fahri. “Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report”. Duzce Medical Journal 28/2 (August 1, 2026): 246-251. https://doi.org/10.18678/dtfd.1904928.
JAMA
1.Kaya M, Bakaç MÖ, Özdemir Ç, Yılmaz F. Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report. Duzce Med J. 2026;28:246–251.
MLA
Kaya, Mustafa, et al. “Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report”. Duzce Medical Journal, vol. 28, no. 2, Aug. 2026, pp. 246-51, doi:10.18678/dtfd.1904928.
Vancouver
1.Mustafa Kaya, Muhammed Ömer Bakaç, Çağla Özdemir, Fahri Yılmaz. Atypical Extraventricular Cystic Subependymal Giant Cell Astrocytoma in a Child Who Did Not Fulfil Clinical Criteria for Tuberous Sclerosis Complex: A Diagnostic Pitfall—A Case Report. Duzce Med J. 2026 Aug. 1;28(2):246-51. doi:10.18678/dtfd.1904928