No Intense 18F-Fluorodeoxyglucose Uptake in Positron Emission Tomography of a Metastatic Orbital Tumor From Breast Carcinoma.

A 47-year-old woman with a history of invasive ductal carcinoma in the right breast reported decreased vision in the OD for the past 3 months. Her best corrected visual acuity was 0.1 OD and 1.0 OS. T1-weighted MRI revealed enlargement of the right lateral rectus muscle with a faint tumor outline and no contrast enhancement in the lesion. F-fluorodeoxyglucose positron emission tomography did not demonstrate intense uptake at the lesion. Because the patient demonstrated optic neuropathy due to compression by the enlarged muscle, balanced orbital decompression (of the deep lateral and medial orbital walls) was performed simultaneously with a tumor biopsy. Visual acuity of the OD was dramatically improved to 1.0. The histopathological examination demonstrated similar findings to her breast carcinoma. F-fluorodeoxyglucose positron emission tomography does not always show a positive result for an orbital tumor that has metastasized from the breast.