Gemistocytic astrocytoma (historical)

Last revised by Frank Gaillard on 18 Dec 2021

Gemistocytic astrocytomas were considered a specific type of diffuse astrocytic tumor, characterized by a prominent component of gemistocytes on histology, whereas now gemistocytic differentiation is merely a recognized pattern observed in astrocytic tumors. In either case, these tumors have a poorer prognosis than other matched WHO grade tumors, and with no characteristic imaging features. 

In the 5th edition (2021) of the WHO classification of CNS tumors, the term gemistocytic astrocytoma is no longer recognized as a specific diagnosis 5. Rather, gemistocytic differentiation is a feature that may be observed in both IDH mutant and wild-type astrocytic tumors. Occasional gemistocytes are, however, frequently seen and therefore an arbitrary cutoff of 20% population of gemistocytes is recommended before the term "gemistocytic tissue pattern" is used 5

For a general discussion of clinical presentation, epidemiology, treatment please refer to astrocytoma, IDH mutant

Gemistocytic astrocytomas were characterized by a significant gemistocytes population, which are large cells with their cytoplasm filled with eosinophilic material displacing the nucleus eccentrically 1.

It is important to note that other gliomas (e.g. fibrillary astrocytoma and oligodendrogliomas) occasionally demonstrated gemistocytes, without being designated gemistocytic astrocytomas. 

Although there were no specific features that allowed pre-biopsy diagnosis, gemistocytic astrocytomas were almost always supratentorial and usually located in the frontal lobes 4

In general gemistocytic astrocytomas demonstrated a more aggressive behavior compared to fibrillary astrocytomas 1-3. Some authors suggested that they should be considered WHO III tumors 2.  

The median survival with treatment is only 2.5 years, with a 5-year survival rate of 30% which was significantly worse than other low-grade gliomas 4. Older age at presentation appeared to be a poor prognostic sign 4

Given the generally worse prognosis, most clinicians favored a more aggressive approach to treatment. 

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Cases and figures

  • Figure 1: gemistocytic cells with eosinophilic cytoplasm
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  • Case 1
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  • Case 2
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  • Case 3: anaplastic
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  • Case 4
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