Clinical Utility of 18F-FDG PET/CT in the Assessment of Mantle Cell Lymphoma With Intraorbital Involvement: A Case Report and Literature Review.

Mantle cell lymphoma (MCL) is an aggressive subtype of non-Hodgkin lymphoma with heterogeneous clinical presentations in which orbital involvement is uncommon. We present the case of a 66-year-old woman with progressive facial swelling, disseminated cutaneous lesions, and blurred vision in the left eye. A skin biopsy confirmed the diagnosis of MCL. Contrast-enhanced computed tomography demonstrated cervical lymphadenopathy and periocular masses. A fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) study revealed increased metabolic uptake in an intraconal lesion within the left orbit in close relationship with the globe and the optic nerve, as well as nodal and extranodal involvement in multiple regions, suggesting intraorbital extranodal extension of MCL. This case highlights the potential value of 18F-FDG PET/CT in identifying intraorbital involvement and providing additional information for staging and therapeutic planning. Evidence regarding the role of 18F-FDG PET/CT in orbital manifestations of MCL remains limited, and additional studies are needed to better define its clinical utility in this setting.