Neuropathology

Angiocentric Glioma, WHO Grade I

Arie Perry
Washington University School of Medicine
St. Louis, MO


Clinical History
The patient is a 24-year woman who presented with a history of partial seizures since the age of 13. EEG mapped her seizure focus to the left medial temporo-occipital lobe and MR images showed a vaguely enhancing, T2/FLAIR hyperintense, gyriform lesion in the same region. The lesion was slightly enlarged compared to studies performed 8 years and 1 year previously. Therefore, a surgical resection was performed. There is no evidence of recurrence after one year of clinical followup.


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Figure 1
T2-weighted MRI showing a bright gyriform lesion involving the cortex of the left medial temporo-occipital lobe.
Figure 2
Moderately cellular intracortical tumor with nuclear palisading in subpial and perivascular regions.
Figure 3
The tumor cells have oval to elongate nuclei with delicate fibrillary processes, reminiscent of astrocytoma.

Figure 4
Perivascular nuclear free zone resembling the pseudorosettes of ependymoma.
Figure 5
Subpial palisades with nuclei arranged both perpendicular and parallel to the pial surface.
Figure 6
Perivascular and subpial aggregates of tumor cells.

Figure 7
GFAP stain highlighting thin tumoral processes, some of which radiate towards blood vessels.
Figure 8
The immunostain for neurofilament protein highlighted numerous entrapped axons, consistent with an infiltrative growth pattern. The angiocentric tumor pattern is also highlighted in relief.

Figure 9
A subset of tumor cells displayed dot-like cytoplasm immunoreactivity for epithelial membrane antigen (EMA).
Figure 10
Electron microscopy revealed spindled tumor cells with electron dense cytoplasm rich in intermediate filaments and numerous microvilli.

Differential Diagnosis
  1. Angiocentric glioma, WHO grade I

  2. Diffuse astrocytoma, WHO grade II

  3. Tanycytic ependymoma, WHO grade II

Final Diagnosis
Angiocentric glioma, WHO grade I

Key words:
brain tumor, angiocentric glioma, ependymoma, WHO

References
  1. Burger PC, Jouvet A, Preusser M et al. Angiocentric glioma. In: Louis DN, Ohgaki H, Wiestler OD and Cavenee WK eds. WHO classification of tumours of the central nervous system. Lyon: IARC, 2007: 92-93.

  2. Lellouch-Tubiana A, Boddaert N, Bourgeois M et al. Angiocentric neuroepithelial tumor (ANET): a new epilepsy-related clinicopathological entity with distinctive MRI. Brain Pathol 2005; 15: 4: 281-6.

  3. Wang M, Tihan T, Rojiani AM et al. Monomorphous angiocentric glioma: a distinctive epileptogenic neoplasm with features of infiltrating astrocytoma and ependymoma. J Neuropathol Exp Neurol 2005; 64: 10: 875-81.