Subependymal giant cell astrocytoma

Incidence

Subependymal giant cell astrocytoma is extremely rare.

Macroscopic appearance and general characteristics

- Subependymal giant cell astrocytoma is an intraventricular astrocytoma of the circumscribed type that occurs in 15% of patients with tuberous sclerosis or Pringle-Bourneville disease. Isolated cases are extremely rare. The tumor is thought to originate from the subependymal calcified tubers that are classically described in tuberous sclerosis.

- The mass is typically multilobulated with peripheral calcification and located near the foramen of Monro, which is easily obstructed. The mass can extend into the third ventricle.

- The tumor occurs in young patients and displays slow growth. It corresponds to Grade I.

Microscopic appearance (images 2 - 3)

The subependymal giant cell astrocytoma is composed mainly of large plump cells resembling astrocytes or neurons. Common features include perivascular pseudopalisading and clustering of tumor cells.

Imaging features (see case reports)

- On non-contrast CT an isointense intraventricular mass with peripherally located dense nodular calcifications is seen. Enhancement is intense and homogeneous. Usually other subependymal or parenchymal calcifications are seen.

- On MRI the tumor is heterogeneous both on T1 and T2 weighted images. On T2 WI besides hyperintense foci, hypointense areas and strongly hypointense zones due to calcifications are seen. On T1 WI the lesion is mixed hypo- to isointense.

Intense but inhomogeneous enhancement can be seen after contrast administration (image 4). Although the subependymal calcifications are usually less well visualised on MRI, other signs of tuberous sclerosis such as cortical tubers are better seen than with CT.

Case reports

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Giant cell astrocytoma

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