A 50-year-old woman visited our hospital for two palpable masses on her sternal and left upper abdominal areas. She had augmentation mammoplasty 12 years prior. Based on the physical examination, the mass in the sternal area was firm, movable, and round. The size of the mass was approximately 3.0x3.0x1.0 cm3. The mass in the upper-left abdomen showed similar characteristics, with a size of approximately 10.0x15.0x1.5 cm3. Ultrasonography revealed a 3.9x1.0x3.4 cm3 hypoechoic lesion in the sternal area. On enhanced-mode computed tomography, a rupture of the left breast implant was noted. Both masses had similar densities as the implant. After rupture of the breast implant, surgery was performed under general anesthesia. Using an inframammary approach, both breast implants and masses were removed using the site of the previous mammoplasty incision. Intraoperative findings revealed that the left breast implant was ruptured and the masses consisted of implant gel components. After surgery, the patient's recovery was uneventful. The patient was discharged without any problem on hospital day 9.