CNS & pituitary tumors

Gliomas, glioneuronal tumors, and neuronal tumors

Other astrocytic tumors

Subependymal giant cell astrocytoma

Last author update: 1 March 2012
Last staff update: 29 November 2023 (update in progress)

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PubMed Search: Subependymal giant cell astrocytoma [title] (SEGA)

Eman Abdelzaher, M.D., Ph.D.
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Cite this page: Abdelzaher E. Subependymal giant cell astrocytoma. website. Accessed February 22nd, 2024.
Definition / general
  • Benign, slowly growing tumor typically arising in wall of lateral ventricles and composed of large ganglioid astrocytes
  • Usually associated with tuberous sclerosis, an autosomal dominant syndrome due to mutations in TSC1 gene on #9q34 (hamartin protein) and TSC2 gene on #16p13.3 (tuberin protein)
  • WHO grade 1

Major features
  • Facial angiofibromas or forehead plaque
  • Nontraumatic ungual or periungual fibroma
  • Hypomelanotic macules (more than 3)
  • Shagreen patch (connective tissue nevus)
  • Multiple retinal nodular hamartomas
  • Cortical tuber
  • Subependymal nodule
  • Subependymal giant cell astrocytoma
  • Cardiac rhabdomyoma, single or multiple
  • Lymphangiomatosis
  • Renal angiomyolipoma

Minor features
  • Multiple randomly distributed pits in dental enamel
  • Hamartomatous rectal polyps
  • Bone cysts
  • Cerebral white matter migration lines
  • Gingival fibromas
  • Nonrenal hamartomas
  • Retinal achromic patch
  • "Confetti" skin lesions
  • Multiple renal cysts

  • Definite TSC: either 2 major features or 1 major feature with 2 minor features
  • Probable TSC: 1 major feature and 1 minor feature
  • Possible TSC: either 1 major feature or 2 or more minor features

  • Tuberous sclerosis also associated with pulmonary and uterine lymphangiomyomatosis, renal angiomyolipoma, cardiac rhabdomyoma
  • SEGA present in 6% of tuberous sclerosis patients
Radiology images

Images hosted on other servers:

Enhancing mass in the third ventricle

Case reports
  • 20 year old woman with solitary subependymal giant cell astrocytoma and mutation of TSC2 gene in tumor but not in somatic cells (J Mol Diagn 2005;7:544)
Gross description
  • Circumscribed, often calcified
Microscopic (histologic) description
  • Composed mainly of large polygonal to elongate cells resembling astrocytes or ganglion cells with abundant, finely granular eosinophilic cytoplasm, bright pink cellular processes, large round / oval nuclei, prominent nucleoli
  • Perivascular pseudorosette formation is common
  • Infiltration of mast cells and lymphocytes is common
  • No Nissl substance in cytoplasm
  • Presence of mitoses, vascular proliferation or necrosis does NOT indicate anaplastic progression
Positive stains
  • Mixed glioneuronal phenotype
  • GFAP+, S100+, also neurofilament proteins, neuronal associated class III β-tubulin
Negative stains
  • HMB45 (unlike other tuberous sclerosis related lesions)
Differential diagnosis
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