The Eye-Black Sign on 18F-FDG PET/CT in Endometrial Adenocarcinoma Without Prior Systemic Therapy: A Rare Imaging Pitfall.

Incidental findings on 18F-FDG PET/CT may mimic pathologic processes, making recognition of imaging pitfalls essential. The eye-black sign, a rare finding characterized by bilateral symmetric FDG uptake in the lower eyelids, has mainly been reported in patients receiving systemic oncologic therapy. We present a 53-year-old woman with endometrial adenocarcinoma treated surgically and with adjuvant vaginal brachytherapy, without systemic therapy. Follow-up PET/CT 18 months later showed bilateral lower eyelid uptake (SUVmax: 9.7) without recurrence. Biopsy revealed chronic inflammatory changes. This case demonstrates that the eye-black sign can occur without systemic therapy and should be recognized as a benign imaging pitfall.