Figure 1: This subependymal giant-cell astrocytoma (SEGA) is present in its typical location at the foramen of Monro. This lesion is larger than should be seen for other subependymal nodules in tuberous sclerosis. (Left) A FLAIR image demonstrates multiple subcortical hyperintense tubers. A hyperintense right posterior periventricular nodule is also visible. Other calcified subependymal nodules are less evident. (Right) Postcontrast T1WI demonstrates the avid enhancement typical of SEGAs.
- Benign tumor of neuroglial origin classically arising in patients with tuberous sclerosis complex (TSC)
- Slow-growing tumor arising in region of germinal matrix, usually near the foramen of Monro, where it can obstruct ventricular outflow, resulting in noncommunicating hydrocephalus
- WHO grade I
- May arise from subependymal nodules (SENs) near germinal matrix
- Represents a neuroglial migration abnormality
- Most common are CNS tumors in patients with TSC
- Uncommonly arises in the absence of TSC
- Similar histology to SENs with diagnosis of SEGA based on tumor size and growth
- Autosomal dominant inheritance or de novo mutations of TSC1 and TSC2 genes
- Afflicts children and young adults with TSC (mean age, 11 years)
- Presenting symptoms
- Obstructive hydrocephalus
- Headache, nausea, vomiting from increased intracranial pressure
- Rarely, spontaneous tumoral hemorrhage with intraventricular extension
- Worsening seizures/epilepsy
- Good prognosis/curable with total surgical resection
- Treatment: rapamycin and/or surgical resection
- Slowly enlarging, avidly enhancing mass arising near the lateral ventricles/foramen of Monro in patients with TSC
- Well-defined tumor margins, often lobulated or “frond-like”
- Variable size
- Additional findings of TSC (cortical tubers/dysplasias, SENs)
- Heterogeneously hypodense to isodense to gray matter
- May show calcification, hydrocephalus
- Strong but heterogeneous enhancement on contrast-enhanced CT imaging
- T1WI: hypointense to isointense to gray matter; areas of calcification can appear hyperintense
- T2WI: heterogeneously isointense to hyperintense; calcification appearing hypointense
- FLAIR: heterogeneously hyperintense, periventricular hyperintensity secondary to acute hydrocephalus and transependymal flow of cerebrospinal fluid
- T2*/GRE/SWI: black susceptibility artifact from foci of calcification
- T1WI+C: avid enhancement
- DWI: relatively reduced diffusion compared with TSC hamartomas
- MRI with contrast, imaging surveillance of enlarging SENs/SEGA
For more information, please see the corresponding chapter in Radiopaedia.
Contributor: Rachel Seltman, MD
Kalantari BN, Salamon N. Neuroimaging of tuberous sclerosis: spectrum of pathologic findings and frontiers in imaging. AJR Am J Roentgenol 2008;190: W304–W309. doi.org/10.2214/AJR.07.2928.
Louis DN, Ohgaki H, Wiestler OD, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97–109. doi.org/10.1007/s00401-007-0243-4.
Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Elsevier, Philadelphia, PA; 2016.
Roth J, Roach ES, Bartels U, et al. Subependymal giant cell astrocytoma: diagnosis, screening, and treatment. Recommendations from the International Tuberous Sclerosis Complex Consensus Conference 2012. Pediatr Neurol 2013;49:439–444. doi.org/10.1016/j.pediatrneurol.2013.08.017.
Sener RN. Diffusion MR imaging of giant cell tumors in tuberous sclerosis. J Comput Assist Tomogr 2003;27:431–433. doi.org/10.1097/00004728-200305000-00023.
Smith A, Smirniotopoulos J, Horkanyne-Szakaly I. From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation. Radiographics 2013;33: 21–43. doi.org/10.1148/rg.331125192.
Please login to post a comment.