Incidental bone metastases on tc-99m-exametazime brain perfusion spect

Brain perfusion scintigraphy with Tc-99m-exametazime (HMPAO) in a 72-year old woman with mild cognitive and behavioral deterioration showed extracerebral tracer accumulation in lytic bone metastases in the frontal and occipital bone. These were confirmed by MRI and could be related to progression of known bone invasion by breast carcinoma. Uptake of exametazime into extracerebral tumours has been described, but this appears to be the first case reported in breast carcinoma. In vitro work has documented the ability of breast cancer cell lines to accumulate exametazime. Clinically, it is important to realise that extracerebral uptake as seen on brain perfusion SPECT with exametazime can signify bone metastases.