Abstract
A 71―year―old woman was admitted to our department with suspected bilateral breast cancer due to positive findings of 18F―FDG PET/CT（PET/CT）scan imaging. The standard uptake value （SUVmax）of 18F―FDG on the breast nodules was 4.9 and 5.0, respectively. The suspected bilateral breast tumors were larger than 3cm. Since the patient had undergone augmentation mammoplasty in her twenties and some foreign material might have been injected, we suspected foreign body granuloma. Dynamic magnetic resonance imaging（MRI）showed a slow―persist pattern in the bilateral breast tumors. Diffusion―weighted MRI images showed low breast signals, suggesting a benign profile. Pathological examination of core needle biopsy specimens revealed accumulation of foamy cells that were positively stained for CD 68 and negative for S 100 protein. The breast tumors were diagnosed as lipogranuloma due to silicone injection. Periodical examinations for more than 4 years have revealed no pathological changes in either breast. For diagnosis of breast silicone granuloma it is important to obtain any details of foreign body injection performed in the past. The fact that silicone granuloma due to injection often exists in the retro―mammary space or the pectoralis muscles is helpful for differential diagnosis. Positive PET/CT scan images due to silicone granuloma have been rarely reported. Although it may not be easy to distinguish breast cancer from silicone granuloma after augmentation mammoplasty, the present case and some reports suggests that dynamic MRI could be useful for this purpose, although needle biopsy might be necessary for definitive diagnosis.
