Anaplastic astrocytoma

Case contributed by Dr Bruno Di Muzio

Presentation

First seizure.

Patient Data

Age: 30 years
Gender: Male
CT

CT Brain

There is a large, ill-defined region of white matter hypoattenuation extending from the left frontal lobe with the involvement of the posterior left frontal cortical grey matter at the vertex. No definite enhancing mass or lesion is identified. No calcification. The associated mass effect causes moderate compression of the frontal horn of the left lateral ventricle, frontal sulcal effacement and 5 mm rightward shift of the anterior falx cerebri. No hydrocephalus and no transtentorial herniation. No acute intracranial hemorrhage or extra-axial collection. No suspicious osseous lesions. The imaged paranasal sinuses and mastoid air cells are clear. 

Conclusion: Ill-defined hypodense left frontal lesion with no definite enhancement is nonetheless suspicious for a brain neoplasm, most likely a primary tumor and unlikely to be a metastasis given the patient's age and pattern of involvement. 

MRI

MRI Brain

Intra-axial mass lesion centered on the left superior frontal gyrus measuring 2.7 x 2.6 cm with cortical expansion and diffuse surrounding white matter FLAIR/T2 hyperintense signal change within the left frontal lobe with the involvement of the body of the corpus callosum. The posterior component is more T2 hyperintense and FLAIR hypointense. No susceptibility. No definite restricted diffusion, but antero-medially there is a moderate size region of postcontrast enhancement (some areas gyriform) and with some increased CBV. There is resultant mass-effect with asymmetry of the left lateral ventricle and left-to-right shift of midline structures measuring 4 mm. Spectroscopy shows prominant choline peak with reduction of NAA, increased mI and mild lactate peak. 

Pathology

Pathology

MICROSCOPIC DESCRIPTION: 1-5. Sections show fragments of a moderately hypercellular glioma with prominent background edema. The tumor cells demonstrate variable morphology with specimens 1-3 showing moderate nuclear and cellular pleomorphism with rounded nuclei and perinuclear halos. Specimens 4-5 show increased tumor pleomorphism with scattered bizarre multinucleated tumor cells and frequent mitotic figures (up to 12 per 10hpf). There is prominent perivascular lymphocytic cuffing. No microvascular proliferation or palisaded tumor necrosis is seen. Immunohistochemistry results show tumor cells stain:

  • GFAP Positive Nestin Positive (intermediate)
  • NogoA Negative
  • IDH-1 R132H Positive (mutated)
  • ATRX Positive (not mutated)
  • MGMT Negative (likely methylated)
  • p53 Positive (favors astrocytoma)
  • p16 CDKN2A Negative
  • Topoisomerase labeling index: Approximately 40%.

DIAGNOSIS: 1&2. Brain tissue, frontal tumor: IDH-1 mutated/ATRX wild type anaplastic glioma (WHO grade III), favoring astrocytoma.

SUPPLEMENTARY REPORT FISH for chromosome 1p/19q deletion. 1p36 NO DELETION DETECTED.

Images and report courtesy of the Royal Melbourne Hospital Pathology Department.

Case Discussion

This case illustrates features of an extensive primary brain tumor on the CT presentation, with the clue being its extension with cortical involvement and expansion. MRI later has confirmed appearances suggestive of a glial series tumor, interestingly showing two different imaging components: the most superior and posterior aspect of the lesion, involving the superior frontal gyrus, has a pattern of a low-grade glioma, with typical appearances of what we could to call "protoplasmic astrocytoma" (no longer an entity since the 2016 WHO review); and the most anterior and medial component show features of a high-grade component: low ADC values and enhancement, likely representing a component of progression to a higher grade tumor. 

Histology has shown that mitotic activity and cellular pleomorphism were present (they are absent in low-grade gliomas) and, unlike glioblastomas, they did not demonstrate necrosis or vascular proliferation. So, instead of calling this tumor a diffuse astrocytoma, it represents an anaplastic astrocytoma

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Case information

rID: 57768
Published: 4th Feb 2018
Last edited: 16th Jul 2018
Inclusion in quiz mode: Included

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