Nodular sclerosing adenosis detected as focal uptake on molecular breast imaging

We report a case of nodular sclerosing adenosis presenting as false-positive uptake on molecular breast imaging (MBI). A 51-year-old woman with elevated lifetime risk of breast cancer underwent supplemental MBI which showed focal uptake in the right breast. A corresponding mass was found on ultrasound with subsequent biopsy yielding nodular sclerosing adenosis. After the biopsy results were reviewed, a problem solving breast MR was recommended. Breast MR showed a solitary enhancing right breast mass containing a marker clip, and the sonographic biopsy was then deemed concordant with pathology. While adenosis lesions are known mimickers of malignancy on other breast imaging modalities, their appearance on MBI has not been previously published.