MRI and FDG PET/CT Findings of Primary Orbit Leiomyosarcoma.

Primary leiomyosarcoma of the orbit is extremely rare. Here we report the case of a 32-year-old woman who presented with proptosis and diplopia of the left eye. MRI examination showed a solid mass in the left orbit with invasion to adjacent tissue, and the lesion had intense FDG uptake with SUVmax of 18.7 on F-FDG PET/CT. Primary orbit leiomyosarcoma was diagnosed by surgery-pathology. F-FDG PET/CT has an advantage in excluding secondary or metastatic orbit malignancy.