Solitary plasmacytoma of the sternum detected incidentally by MR imaging of the cervical spine.

We incidentally detected a case of solitary plasmacytoma of the sternum by magnetic resonance (MR) imaging of the cervical spine. At detection, the patient had no symptoms, the lesion was localized in the bone marrow of the sternum, and there were no findings of bone destruction. The lesion showed high contrast on diffusion-weighted images, gradually enlarged over 3 years, and was confirmed as a solitary plasmacytoma at open biopsy 3 years after detection. Radiologists should pay attention to incidental findings in the upper part of the sternum at MR imaging examination of the cervical spine.