Abstract 4- 0945-1000
Category: Clinical

At the end of the session,
participants will be able to:

  1. Optimal utilization of small biopsy specimen is very important in order to facilitate complete molecular work up, from frozen section to making a diagnosis.
  2. Specific histologic/molecular variant should be specified in the diagnostic field.
  3. Further studies are required for unclassified entities.



Dr. Namita Sinha is a neuropathologist at Health Science Center, the University of Manitoba in Winnipeg. Her interest is mainly in tumor pathology. She has over 22 publications with more than 12 publication as first or last author. She is taking Neuropathology review session in CAP residents review course for last three years.


Namita Sinha1 Arie Perry 2,

1 Department of Pathology, Health Sciences Center, University of Manitoba, Winnipeg, MB, Canada

2 Department of Pathology, UCSF, San Francisco, CA, USA

Target Audience:
Pathologists, Residence

Medical Expert (the integrating role), Communicator, Collaborator, Professional

Diagnostic challenges in unusual high-grade gliomas


Diagnosis of most of adult high-grade gliomas is largely based on morphology and immunohistochemistry, with an increasing role of molecular studies to aid proper classification (e.g., IDH wildtype and IDH-mutant gliomas, H3K27M mutant diffuse midline glioma). On occasions, despite all the work-up, the results do not allow for a definite diagnosis that are established in the most recent WHO classification scheme. For instance, some glial tumors are poorly differentiated and loses GFAP expression. In these cases, DNA methylation profiling is a power tool in establishing the diagnosis. Therefore, it is very important that the tissue should be utilized optimally and carefully especially when the biopsies are very small and extensive work may be required. On rare occasions, definitive diagnosis can be challenging despite complete histological and molecular characterization. Some variants of glioblastoma may show epithelial or primitive neuronal differentiation and some variants may have increased predilection for CSF metastasis and therefore it is important to subclassify these variants. These challenges will be discussed with some examples of high-grade gliomas that we received in our institution at Health Sciences Center, University of Manitoba.