Unexpected Finding on Mammography and MRI due to Accumulation of Iron Oxide Particles Used for Sentinel Lymph Node Detection

We present a case with imaging artefacts on mammography and Magnetic Resonance Imaging (MRI) caused by iron oxide particles. After being diagnosed with the medullary cancer of the breast, the female patient had a breast conserving surgery on right breast. Iron oxide particles were used for the detection of the sentinel lymph node during operation. On follow ups, a de novo density on mammography, which was initially thought to be a new tumour, was found. MR images proved that the lesion is an artefact caused by iron oxide accumulation. Our aim in this case study is to underline and discuss the imaging artefacts caused by these particles and raise awareness.