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Pathology/GBM diagnosis and pathology


QUESTION: Hi, my sister was diagnosed with a brain tumor one week ago. She has surgical resection within 24 hours due to size and brain edema. Pathology confirmed GBM. Her pathology reads a glial tumor with extensive geographic necrosis. I know that the necrosis means the tumor was growing faster than the blood supply could support but would you ever get a report that showed no necrosis? Does this give any indication of disease progression or prognosis? Also it states positive for GFAP and EGFR. My understanding of this is that is just confirms it is a GBM, is this true or am I simplifying it? Partial positive for pancytokeratin and P63; negative for EMA, P53 and PR. Ki-67 labels about 10% cells. I cannot figure out what this means, is it good or bad? Thanks so much for your time. I am trying to do research for my sister before we go back to the MD and just want to be as informed as I can be.

ANSWER: Hello Joanne:

GBM as a tumor generally has lots of necrosis, it is an aggressive form of cancer. Yes tumors can have less or no necrosis based on their growth pattern.

Various markers are done as a panel to confirm the origin of the tumor and to see how aggressively it is growing.
GFAP conforms that the tumor is of glial (brain) origin. EMA, P53 and PR are done to see if the tumor is of epithelial, neural or breast origin which it is not as all these are negative.

Ki-67 indicates actively dividing cells and as I mentioned this is an aggressive tumor with 10% positive Ki-67 cells.

It is tough time ahead for your sister, you and the family. I wish her good health.

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for your response. Could you just clarify the Ki-67 indicates actively dividing cells. Her path report states 10% positive- is that out of 100%. Does that mean that 10% of the cells are dividing rapidly. I am still unclear on how to interpret that.

Thanks again.

Based on various studies the cut of of 10% is used to assess prognosis.
<10% Ki-67 has a better prognosis.

However an overall prognosis is established based on  various factors like type of tumor, age of patient, Ki-67 index etc.
again each individual patient is not a statistic and can behave different than the established statistics.


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Neha Dahiya MD


Help patients understand the medical terminology of their lab results and / or tissue biopsy reports.


I am a pathologist and director of clinical laboratory services. I have been a practicing pathologist for last 9 years in a 350 bed multi specialty hospital laboratory in India.

Indian association of pathologists and microbiologists.
International Academy of Cytology
International association of Pathologists - Indian division
Indian association of Cytology

MD (pathology) MBA

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