Deductible medical expenses are expenses paid to treat, cure, prevent or mitigate any disease or condition of the mind or body that affects its normal function. While breast enlargement for purely cosmetic reasons is not eligible, surgery to treat a tumor and reconstructive surgery afterward are certainly deductible medical expenses. (The fact that reconstruction is also partly cosmetic does not stop it from being deductible as part of the treatment or mitigation of a disease.)
Amounts you paid out of pocket are deductible. Amounts reimbursed by insurance, or paid from an HSA or FSA, are not deductible, because you already got a tax break for those payments.
As pointed out, Turbotax is programmed to ask for all your expenses, then to ask for all your reimbursements, and Turbotax will calculate the allowable deduction. I think this is needlessly complicated, but you should follow the program as designed so you don't run into any hiccups.
