Thymoma & Thymic Carcinoma
Thymic epithelial tumours are rare, and thymoma and thymic carcinoma differ substantially in behaviour. Thymoma carries a distinctive association with autoimmune conditions, myasthenia gravis in particular.
Disease categories
Major disease categories
- Thymoma (WHO types A, AB, B1, B2, B3)
- Thymic carcinoma
- Thymic neuroendocrine tumours
Molecular
Molecular considerations
GTF2I alterations are characteristic of indolent thymoma subtypes. Thymic carcinoma carries a different profile, with CDKN2A loss and KIT alterations described in a minority.
Markers commonly discussed in thymoma & thymic carcinoma
- GTF2I
- KIT
- CDKN2A
- PD-L1
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
Profiling is discussed in advanced thymic carcinoma, where the actionable yield differs from thymoma.
Germline
Germline considerations
Not routinely indicated.
Molecular monitoring
ctDNA and liquid biopsy considerations
Investigational.
Single-cell & computation
Single-cell and algorithmic approaches
Single-cell analysis in thoracic malignancy is used to study resistance as it emerges — separating a resistant subclone from the bulk population before it dominates, and characterising the immune contexture that bulk profiling obscures. Single-cell DNA sequencing can establish whether a resistance alteration is present in a minority of cells at baseline rather than acquired later. Algorithmic work includes fusion detection from RNA, subclonal reconstruction across serial samples, and classifiers that distinguish histological transformation from acquired resistance.
Decisions
Treatment decision questions
Questions worth raising with a treating team when a decision is being made:
- Is the distinction between thymoma and thymic carcinoma clearly established?
- Has associated autoimmune disease, particularly myasthenia gravis, been assessed?
- Is the WHO histological type recorded?
Resistance
Resistance and recurrence questions
- Has the histology been revisited on recurrence?
Trials
Clinical trial considerations
Thymoma and thymic carcinoma are frequently enrolled separately; the distinction affects 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.