CNS Tumours
Central nervous system tumours beyond the principal gliomas include spinal cord tumours, pituitary and pineal region tumours, and leptomeningeal disease — each with distinct diagnostic considerations.
Disease categories
Major disease categories
- Spinal cord tumours
- Pituitary tumours
- Pineal region tumours
- Leptomeningeal disease
- Skull base tumours
Molecular
Molecular considerations
Molecular features are entity-specific. DNA methylation profiling has become an important tool for classifying difficult central nervous system tumours.
Markers commonly discussed in cns tumours
- Entity-specific markers
- Methylation class
- H3 K27M (midline)
- BRAF
Not exhaustive, and not every marker is assessed in every patient. Which of these is relevant depends on the individual case and should be discussed with the treating team.
Testing
Genomic testing considerations
Methylation profiling and targeted panels are discussed for diagnostically difficult tumours.
Germline
Germline considerations
Considered where a syndromic pattern is suggested.
Molecular monitoring
ctDNA and liquid biopsy considerations
Cerebrospinal fluid analysis is an area of research interest, particularly in leptomeningeal disease.
Single-cell & computation
Single-cell and algorithmic approaches
Single-cell sequencing in neuro-oncology is used to characterise the cellular hierarchy within a tumour, including the stem-like populations implicated in recurrence, and to describe the immune compartment that bulk profiling represents poorly. Single-cell DNA analysis addresses regional heterogeneity, which is pronounced in glioma. Algorithm work is dominated by DNA methylation classification, which has become one of the more reliable diagnostic tools in difficult central nervous system cases, alongside cerebrospinal fluid analysis methods.
Decisions
Treatment decision questions
Questions worth raising with a treating team when a decision is being made:
- Has the diagnosis been confirmed by a neuropathology service?
- Has methylation profiling been considered?
Resistance
Resistance and recurrence questions
- Has the diagnosis been revisited where the clinical course is unexpected?
Trials
Clinical trial considerations
Entity and molecular class shape eligibility.
When a precision oncology review may help
A review is most useful where the standard pathway has been exhausted or where the picture is more complicated than a protocol accounts for — rare presentations, treatment resistance, complex or apparently contradictory molecular findings, or a decision between several defensible options.
The output is a structured analysis and a set of questions for the treating team. It is not treatment, and it does not replace the treating oncologist.