Monica Long, a U.S. registered nurse, was diagnosed with the earliest stage of breast cancer from a biopsy in 2007, receiving extensive surgery that left Long’s right breast missing a chunk the size of a golf ball. But a year later, she was told the pathologist made a mistake and she’d never had cancer, the New York Times reports. Diagnosing early breast cancer can be surprisingly difficult, the newspaper found, due to error and disagreement over whether cells are malignant or benign. Improvements in imaging technology means smaller potential breast lesions are evident, some the size of a few grains of salt. The U.S. government is funding a nationwide study of variations in breast pathology due to concerns that 17 per cent of cases of ductal carcinoma in situ, or DCIS, done by a commonly used needle biopsy, might be misdiagnosed. There are no requirements now that say pathologists doing the work need specialized expertise.