There are a few possible reasons:
- local infection
- local post op liquid collection
- tumor recurrence
What you need to find out is whether it is growing in size over time. And what is the CT or MRI showing about this swelling.
If you can upload a picture, that might help us.
Next Steps
PET CT +/- MRI
Needle test from the swelling
Health Tips
Be hopeful that it may not be tumor recurrence but evaluation is a must