F-18 FDG PET scan findings in a case of carcinoma of the breast with a rare site of metastases to the gingival region.

Malignant tumors of the breast have an inherent potential to metastasize more often to the regional lymph nodes. It is rare to find a metastasis to the oral region from a primary in the breast, but when this does occur, it usually involves the jawbones rather than the soft tissues. A 33-year-old premenopausal woman, a diagnosed case of locally advanced right breast carcinoma, underwent right modified radical mastectomy followed by chemotherapy as per the institutional protocol. She presented after 2 years with an exophytic growth in the upper alveolar region of the oral cavity. Biopsy indicated gingival metastasis from a poorly differentiated adenocarcinoma of the breast. She was referred for F-18 FDG PET scan to evaluate the disease status before planning radiotherapy to the gingival metastasis. F-18 FDG PET scan was done after intravenous injection of 370 MBq (10 mCi) of tracer. Whole-body PET images were reconstructed in iterative algorithm (OSEM). Whole-body F-18 FDG PET scan showed hypermetabolic foci in the midmaxillary region (SUV max: 6.5), upper end of the right humerus, a large hypermetabolic area in the upper zone of the right lung with contiguous hilar node involvement on the right side of the lung, and an area of intense hypermetabolic activity in the left acetabular and ischial region. The present case demonstrates a rare site of metastasis in the oral region from carcinoma of the breast.