Interesting ImagesTo Identify Small Bowel Metastasis From Lobular Breast Cancer on 18F-Fluoroestradiol PET/CT Necessary to Adjust the Background Uptake LevelLu, Yang MD, PhD Author Information From the Division of Diagnostic Imaging, Department of Nuclear Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX. Received for publication July 30, 2022; revision accepted August 13, 2022. Conflicts of interest and sources of funding: none declared. Correspondence to: Yang Lu, MD, PhD, Division of Diagnostic Imaging, Department of Nuclear Medicine, The University of Texas MD Anderson Cancer Center, Unit Number 1483, 1400 Pressler St, Houston, TX 77030. E-mail: [email protected]. Clinical Nuclear Medicine 48(2):p 192-193, February 2023. | DOI: 10.1097/RLU.0000000000004402 Buy Metrics Abstract A 61-year-old woman was incidentally found to have small bowel metastasis from an undiagnosed lobular breast cancer in a workup for her acute presentation of small bowel obstruction. However, outside-hospital mammogram and breast ultrasound failed to reveal primary breast cancer. At 3.5 months postsurgery, the patient transferred her care to our hospital and received initial staging 18F-fluoroestradiol (FES) PET/CT. The occult primary right breast cancer and previously biopsied right axilla lymph node were visualized on FES PET/CT. The intense small bowel uptake of FES was initially considered as physiological; however, after readjusting the background FES level on PET, an intense focus at small bowel anastomosis site became obvious. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.