Whole-Body Positron Emission Tomography/Computed Tomography Imaging and Staging of Orbital Lymphoma

Objectives To report the use of whole-body positron emission tomography fused with computed tomography (PET/CT) for the diagnosis and staging of orbital lymphoma. Design Retrospective observational case series. Participants Four patients with biopsy-proven orbital lymphoma were evaluated by 18-fluoro-2-deoxyglucose whole-body PET/CT imaging. Methods Positron emission tomography/CT images were studied for the presence of glucose uptake. Foci were considered suspicious based on their standardized uptake values (SUVs). Physiologic images (PET) and their anatomic counterparts (CT) were fused to allow form and function to be evaluated on the same diagnostic page. Main Outcome Measures Positron emission tomography/CT images were assessed for foci with abnormally high SUVs that correlated with biopsy-proven lymphoma. Results Positron emission tomography/CT detected orbital lymphoma in 3 patients (75%). It also revealed systemic lymphoma in 2 of the 4 patients. The 2 patients found to have systemic lymphoma were diagnosed to have extranodal marginal zone B-cell orbital lymphoma of the mucosa-associated lymphoid tissue (MALT) type. Similarly, the 2 with negative PET/CT results also had orbital MALT-type lymphoma. We found that PET/CT imaging helped guide further management in all 4 patients. Conclusions Positron emission tomography/CT should be considered as a new method of diagnosing, staging, and restaging patients with orbital lymphomas.