RESUMO
Objective To investigate CT features of subconjunctival fat prolapse and choristoma. Methods Thirty-eight patients, including 18 with subconjunctival fat prolapse and 20 with choristoma, were retrospectively analyzed. Transverse plain CT scan was performed in all the patients, and then coronal plane images was reconstructed at CT workstation. Results CT features of subconjunctival fat prolapse revealed a crescent-shaped or horn-shaped fat density mass continuous with the orbital fat in the superior temporal quadrant of the orbit. CT features of choristoma revealed a crescent-shaped or triangle fat density mass incontinuous with the orbital fat in the temporal side. Conclusion Subconjunctival fat prolapse typically occurs in bilateral superior temporal quadrant of the orbit in elderly males. Subconjunctival choristoma occurs in the unilateral temporal side in adolescent. CT is helpful to distinguish subconjunctival fat prolapse and choristoma.