at number 8, biopsy blunder. something unusual turns up in 35-year-old derry eason's breast. is it cancer? doctors do a biopsy. her diagnosis, positive. invasive lobular carcinoma. this single mom has breast cancer. she gets a second opinion. two more experts look at her lab work and agree. derry decides she has to be aggressive to save her life. she has surgery to remove both her breasts. and then weeks later a bombshell admission by her doctors. >> they told me basically you didn't have cancer and you never did. >> what makes doctors think she's sick? that biopsy showing she has cancer actually belongs to someone else. a health department investigation says a lab technician is most likely