Figure 1: This small FLAIR-hyperintense (left) intraventricular nodule represents subependymoma, a fairly common and benign tumor. Enhancement is variable, but this example has no significant enhancement on postcontrast T1WI (right).
Figure 2: Often nearly invisible on CT (top row left), subependymomas are intraventricular tumors that are usually much more evident on FLAIR (top row right). This left frontal horn subependymoma demonstrated no appreciable enhancement on postcontrast T1WI (bottom).
Figure 3: Axial non-contrast head CT demonstrates a calcified lesion in the 4th ventricle. Sagittal FLAIR (top row right), axial T1 without contrast (second row left), axial T1 post-contrast (second row right), DWI (third row left), ADC (third row right), and axial T2FS (bottom row) images demonstrate a non-enhancing mass arising from the floor of the 4th ventricle without restricted diffusion. The appearance and location of this lesion are classic for subependymoma.
- Benign, intraventricular tumor likely arising from subependymal glial precursor cells
- WHO grade I
- Solid, avascular, lobulated mass
- Large tumors may show calcification, hemorrhage, and cystic components
- Usually arising from floor of 4th ventricle or septum pellucidum or lateral wall of lateral ventricle
- Afflicts middle-aged or older adults (5th and 6th decades of life)
- Male gender predilection
- Common presenting symptoms
- Usually asymptomatic
- In larger tumors, symptoms are often related to increased intracranial pressure: nausea, vomiting, headaches, ataxia
- Conservative management with serial imaging if asymptomatic
- If symptomatic: gross total resection for lateral ventricular tumors, subtotal resection for 4th ventricle tumors, may require CSF shunt for hydrocephalus
- Recurrence is rare after resection
- Very good prognosis for supratentorial subependymomas
- Well-defined, lobulated, nonenhancing ventricular mass
- 4th ventricular tumors may grow through foramen of Magendie
- Iso- to hypodense
- ± Calcification and cysts in larger tumors
- Usually little to no enhancement on contrast-enhanced CT
- T1WI: homogenous, hypo- to isointense relative to white matter
- T2WI: hyperintense; heterogeneous signal due to cystic components and hemorrhage in larger tumors
- FLAIR: hyperintense, no edema of adjacent brain parenchyma
- T2*/GRE/SWI: signal blooming secondary to calcification
- T1WI+C: little to no enhancement most common
Bi Z, et al. Clinical, radiological, and pathological features in 43 cases of intracranial subependymoma. J Neurosurg. 2015;122:49-60.
Chiechi MV, et al. Intracranial subependymomas: CT and MR imaging features in 24 cases. AJR Am J Roentgenol. 1995;165:1245-1250.
Hou Z, et al. Clinical features and management of intracranial subependymomas in children. J Clin Neurosci. 2013;20:84-88.
Louis DN, et al. WHO Classification of Tumours of the Central Nervous System: Subependymoma. Lyon: IARC Press, 2007; 70-71.
Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed.). Philadelphia, PA: Elsevier, 2016.
Smith AB, et al. From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation. Radiographics. 2013;33:21-43.
Silverstein JE, et al. MRI of intracranial subependymomas. J Comput Assist Tomogr. 1995;19:264-267.
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