For most brain and spine tumors, the pathological evaluation of tumor tissue is key to planning the most effective treatment. The Brain and Spine Tumor Program includes a board-certified neuropathologist — a pathologist with special training in diagnosing abnormalities of the brain, spine and other nerve tissues.
Permanent Section DiagnosisAfter a brain or spine tumor is removed during surgery (or tumor tissue is obtained through a needle biopsy procedure), it is sent to the pathology lab. A sample of the tumor is processed, fixed in paraffin and sliced into very thin sections. The sections are then stained with chemicals that provide contrast to aid examination under a light microscope.
In general, tumor tissue samples are evaluated in terms of how different they are from normal brain or spine tissue. Key tumor characteristics include:
- Shape and size (many cancer cells have a distinctive form)
- Hypercellularity (tumor tissue tends to feature many cells crowded together)
- Evidence of rapid division (certain structures identify cells that are proliferating quickly)
- An abundance of blood vessels (tumors establish their own blood supply)
- Necrosis (many high-grade tumors grow so quickly that they outstrip their blood supply, resulting in areas of tumor cell death)
The neuropathologist’s final diagnosis of cancer type and grade is presented at the weekly tumor board meeting of the Brain and Spine Tumor Program. During the meeting, the care team might discuss the need for additional pathological tests, including any tumor cell genetic studies that could help shape the treatment approach.
Frozen Section AnalysisDuring some brain surgeries, a surgeon will remove a small portion of abnormal tissue for immediate analysis. The tissue is frozen, cut into thin slices, then evaluated under a microscope. Frozen tumor sections are not as high-quality as permanent section samples, but they allow the neuropathologist to make a preliminary diagnosis while the patient is still in the operating room. Based on these initial findings, the surgeon may remove additional samples, proceed with a larger resection, modify the surgical plan or conclude the procedure.
Brain Tumor Gene StudiesPatients who have the same type of tumor often respond very differently to treatment. Researchers are finding that this can be the result of differences in the genetics of individual tumors. Tests that analyze the genetic structure of tumor cells are becoming increasingly important in neurological cancer.
The Brain and Spine Tumor Program offers the most up-to-date cytogenetic testing available. Currently, brain tumor gene testing does not determine specific drug treatments, but it can provide prognostic information that helps physicians make decisions about the timing of treatment.
Last Review Date: Sept. 30, 2010
Online Editor(s): Richard Petre