Breast Carcinoma Shown on 99mTc-HYNIC-TOC Study Performed to Evaluate Tumor-Induced Osteomalacia.

A 74-year-old woman with a history of suspected tumor-induced osteomalacia underwent 99mTc-HYNIC-TOC scintigraphy to search potential culprit tumor. The images showed one in the middle shaft of left femur without corresponding morphology change on the CT portion of the subsequent SPECT/CT images. The patient declined surgical exploration of the left femur. Another activity was in the right breast, which was resected and pathologically confirmed as breast carcinoma. Postsurgically, the patient's symptoms were not improved. Four years later, a repeat 99mTc-HYNIC-TOC scintigraphy showed more prominent activity in the left femur with gross abnormality on the corresponding CT images.