Introduction. Orbital localization of follicular lymphoma is exceedingly rare, and its diagnosis is often challenged due to a broad spectrum of ophthalmic differential diagnoses. We report a case of orbital relapse of follicular lymphoma detected five years after complete remission using 18F-fluorodeoxyglucose positron emission tomography with computed tomography. Case Report. A 53-yearold man diagnosed with follicular lymphoma in 2013 achieved complete remission following chemotherapy in 2017 and remained under routine follow-up for the subsequent five years. In 2022, he presented with a 10-day history of right orbital pain. Clinical examination revealed right-sided exophthalmos and eyelid ptosis. 18F-fluorodeoxyglucose positron emission tomography with computed tomography demonstrated increased metabolic activity in the right orbit, raising suspicion of disease relapse. Subsequent ophthalmologic assessment and additional imaging confirmed the presence of an orbital mass, which was surgically excised. Histopathological analysis verified a localized orbital recurrence of follicular lymphoma. The patient was subsequently treated with localized radiotherapy. Follow-up 18F-fluorodeoxyglucose positron emission tomography with computed tomography performed in 2023 demonstrated a complete metabolic response. Conclusion. The case highlights the important role of 18F-fluorodeoxyglucose positron emission tomography with computed tomography in detecting atypical and rare manifestations of follicular lymphoma. Integration of 18Ffluorodeoxyglucose positron emission tomography/computed tomography findings with ophthalmologic evaluation and histopathological confirmation is essential for accurate diagnosis and appropriate therapeutic decision-making.
Kotur et al. (Wed,) studied this question.