Subepandymal giant cell astrocytoma (SEGA) and Gemistocytic astrocytoma are often difficult to differentiate.
Here are a few differences between SEGA and Gemistocytic astrocytoma

1. LOCATION
2. INFILTRATION TO ADJACENT PARENCHYMA
3. HISTOPATHOLOGY
4. WHO GRADE
5. MUTATIONS
6. PROGNOSIS

A quick summary for you!

1.Location:

SEGA is often intraventricular in location wheras Gemistocytic astrocytoma is intraparenchymal.

2.Infiltration to adjacent parenchyma:

SEGA is non Infiltrative, wheras Gemistocytic astrocytoma shoes infiltration to adjacent parenchyma.

3.Histopathology:

Both SEGA and Gemistocytic astrocytoma have cells with eosinophilic cells with prominent nucleoli. However, cells of SEGA are larger than those of Gemistocytic astrocytoma. Perivascular pseudorosettes can be found in SEGA and Perivascular lymphocyte cuffing is found in Gemistocytic astrocytoma. Mast cells and lymphocytes may be present in SEGA. Atypia, mitosis, necrosis and vascular proliferation may be present in SEGA but they are absent in Gemistocytic astrocytoma.

4.WHO GRADE:

SEGA is grade I and Gemistocytic astrocytoma is grade II.

5.Mutations :

SEGA if associated with tuberous sclerosis and show germline mutations in TSC1/TSC2 gene. Gemistocytic astrocytoma shows mutations in IDH and TP53.

6.Prognosis:

SEGA has a better prognosis when compared with Gemistocytic astrocytoma.

REVIEW QUESTION– SEGA and Gemistocytic astrocytoma

A brain tumor was identified in the intraventricular location of a 20 year old female who also had facial plaques and hypopigmented macules. Tumor cells were large with glassy eosinophilic cytoplasm and a prominent nucleoli. Perivascular pseudorosettes could be identified in some sections. Which of the following is true regarding this tumor?

A) It is a WHO grade IV tumor
B) Aggressive tumor
C) Occurs in 100% patients with von hippel lindau disease.
D) Immunostaining for glial fibrillary acidic protein is positive.

Differences between gliosis and glioma is HERE!

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