Hi!
The type of uterine cancer that we see most often is endometrial cancer, and given her age and the fact that she had a baby not long ago, the chance of that type of cancer is almost zero. Even hyperplasia which is what we usually find when the "lining is thickened" is pretty unlikely--hyperplasia is pre-cancerous and caused by hormone imbalance.
It is possible that there is still some residual tissue left over from delivery, although this seems unlikely this much later.
The most probable diagnosis is going to be a submucosal fibroid or a polyp, both of those are benign, and the cure is a D&C. Endometritis, or low grade infection of the uterine lining would also be up high on my list of diferential diagnoses--this is treated with antibiotics and diagnosed with D&C.
To be complete, I should mention the possibility of gestational trophoblastic disease, which is an EXTREMELY rare growth of placental tissues that happens after a baby is delivered. Very rarely some cells of the placenta continue to grow instead of sloughing off. This is SO uncommon that it is hardly even worth mentioning, and definitely not worth worrying about.
Hope all goes well with surgery. Are you babysitting while she goes in? Good luck!
Dr B
Yes, I am babysitting for her. We have to pick up the older brother from High School,
the other older brother from private school, and the baby from daycare. Then run the two boys for a haircut. Needless to say, Grandma will be busy.
Thanks