Anaplastic astrocytoma IDH wildtype (pineal region)

Case contributed by Frank Gaillard
Diagnosis certain


2 weeks of worsening headaches and blurred vision

Patient Data

Age: 45 years
Gender: Female

There is a mass in the quadrigeminal plate cistern which is homogeneously mildly T2 hyper- and T1 hypointense to grey matter which demonstrates avid heterogeneous contrast enhancement. There is abnormal signal also extending into the thalami, more marked on the right. It diffusion restricts. 

There is increased blood volume in the lesion. The MRS shows increased choline-creatine ratio with reduced NAA peak in keeping with a high-grade tumor trace.

There is obstruction of the cerebral aqueduct with hydrocephalus involving the lateral and third ventricles. Mild periventricular T2 hyperintensity suggests a degree of transependymal edema.

The patient went on to have a craniotomy and excision of the tumor. The mass was inseparable from both the pineal gland and the left thalamus. A clear site of origin could not be established. 



MICROSCOPIC DESCRIPTION: Paraffin sections show a densely hypercellular glial tumor with strong immunostaining for GFAP and nestin indicating astrocytic differentiation. There is moderate nuclear and cellular pleomorphism.  Moderate numbers of mitotic figures are identified. Vessels are prominent throughout the tumor. These are enclosed within sleeves of fibrous tissue and do not show endothelial cell hyperplasia. No necrosis is seen. Moderate numbers of cells show strong immunostaining for synaptophysin. These are interpreted as incorporated pineocytes.  No immunostaining for NeuN or IDH-1 is seen.

Interpase FISH: 

  • 1p36 - No loss detected 
  • 19q13 - No loss detected

FINAL DIAGNOSIS: Anaplastic astrocytoma (WHO Grade III)

Note: Although this tumor is entirely consistent with IDH wild-type molecular subtype, strictly speaking, to conclusively establish this, IDH would need to be sequenced to ensure that a non-IDH1 R132H mutation was present. In practice, an IDH1 R132H negative tumor in an individual over 55-years-of-age makes the possibility of this being IDH mutant remote (<1%), and sequencing is not felt to be necessary by many institutions, and not recommended by the WHO classification of CNS tumors (2016). 

Case Discussion

As is the case elsewhere, one must not focus exclusively on lesions typical of a specific location. In this instance, astrocytomas of the pineal or nearby parenchyma must be considered when a pineal region mass is found. 

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