Navigation-assisted resection of a primary extraocular melanoma of the orbit.

UNLABELLED A 22-year-old male presented with proptosis of the right eye and diplopia. On magnetic resonance images (MRI), a well-delineated orbital tumor medio-distal to the eye was detected, respecting the eye-ball and the orbital walls. The aim of navigation-assisted surgery was to excise the progressive tumor while maintaining vision. A modified latero-cranial orbitotomy was used to approach the tumor. Microscopic analysis of the resection specimen revealed a melanoma. The patient's postoperative course was uneventful. The diplopia improved rapidly. Two further eye-saving second-look revisions of the tumor site excluded further melanoma infiltrates and revealed melanophages in scar tissue. Intraoperative navigation was used during all procedures. The tumor showed some interesting features concerning its histopathological appearance and magnetic resonance imaging. Detailed histopathological investigations supported the decision for organ-saving surgery. Follow-up MRI and positron emission tomograms up to 14 months later showed neither local tumor recurrence nor distant spread. CONCLUSION In the presented case with the incidental finding of orbital melanoma without invasion of the globe or orbital walls, navigation-assisted surgery supported the eye-saving operating procedures.