ePoster
Abstracts/Presentation Description
Jessica Berger1, Ricardo Vilain1, Frank Alvaro2
1Department of Anatomical Pathology, John Hunter Hospital, Newcastle, NSW, Australia
2Department of Paediatric Oncology, John Hunter Hospital, Newcastle, NSW, Australia
Introduction
Our case of anaplastic epithelioid pleomorphic xanthoastrocytoma (aePXA) is a rare variant of WHO Grade 3 PXA with a morphological and molecular mimic. Its doppelganger, the epithelioid variant of glioblastoma (eGBM) has been recently stratified to include the PXA-like eGBM subtype (1, 2). In light of our case’s resemblance with PXA-like eGBM, we compared the features of aePXA and its pathological cousins to illustrate a diagnostic pitfall.
1Department of Anatomical Pathology, John Hunter Hospital, Newcastle, NSW, Australia
2Department of Paediatric Oncology, John Hunter Hospital, Newcastle, NSW, Australia
Introduction
Our case of anaplastic epithelioid pleomorphic xanthoastrocytoma (aePXA) is a rare variant of WHO Grade 3 PXA with a morphological and molecular mimic. Its doppelganger, the epithelioid variant of glioblastoma (eGBM) has been recently stratified to include the PXA-like eGBM subtype (1, 2). In light of our case’s resemblance with PXA-like eGBM, we compared the features of aePXA and its pathological cousins to illustrate a diagnostic pitfall.
Case report
A 13 year old male with a 6cm brain tumour exhibited epithelioid morphology, microvascular proliferation and necrosis, bearing a striking similarity to eGBM. The final diagnosis was anaplastic epithelioid, WHO Grade 3 PXA. We reviewed the literature and provided tables with comparison of features between classical PXA, aePXA and PXA-like GBMs.
A 13 year old male with a 6cm brain tumour exhibited epithelioid morphology, microvascular proliferation and necrosis, bearing a striking similarity to eGBM. The final diagnosis was anaplastic epithelioid, WHO Grade 3 PXA. We reviewed the literature and provided tables with comparison of features between classical PXA, aePXA and PXA-like GBMs.
Discussion
aePXA and PXA-like eGBM show significant overlap in clinical and pathological features. We conclude that aePXA and PXA-like eGBM are so closely related, that they are only distinguishable by the identification of a classical PXA precursor with eosinophilic granular bodies in the former. As in our case, such eosinophilic bodies can be focal, largely overrun by high grade transformation or in other instances, potentially unsampled (3). The relationship between eGBM and the malignant progression of PXA needs further clarification. Whether subtypes of these two tumours will be considered as the same or closely related entities in future WHO nomenclature remains to be elucidated. (219 words)
aePXA and PXA-like eGBM show significant overlap in clinical and pathological features. We conclude that aePXA and PXA-like eGBM are so closely related, that they are only distinguishable by the identification of a classical PXA precursor with eosinophilic granular bodies in the former. As in our case, such eosinophilic bodies can be focal, largely overrun by high grade transformation or in other instances, potentially unsampled (3). The relationship between eGBM and the malignant progression of PXA needs further clarification. Whether subtypes of these two tumours will be considered as the same or closely related entities in future WHO nomenclature remains to be elucidated. (219 words)
Statement of originality: This work is original and contributed by the authors.
References
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- Giannini, C., Figarella-Branger, D., Jacques, T.S., Paulus, W., Tabori, U., Capper, D., and Jones, D.T.W. Pleomorphic xanthoastrocytoma. In: WHO Classification of Tumours Editorial Board Central nervous system tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2021 [cited 2024 August 31]. (WHO classification of tumours series, 5th ed.; vol. 6). Available from: https://tumourclassification.iarc.who.int/chapters/45.
- Alexandrescu, S., Korshunov, A., Lai, S.H., Dabiri, S., Patil, S., Li, R., Shih, C.-S., Bonnin, J.M., Baker, J.A., Du, E., Scharnhorst, D.W., Samuel, D., Ellison, D.W. and Perry, A. (2016), Epithelioid GBM and Anaplastic Epithelioid PXA. Brain Pathology, 26: 215-223.
Speaker/Presenting Authors
Authors
Submitting/Presenting Authors
Dr Jessica Berger -