BACKGROUND: Neuromuscular hamartoma is a very rare tumor; with only five cases reported in the orbit. It often occurs in infants and young children and involves large peripheral nerves, but there has been only few reports of occurrence in the orbit and adults.
METHODS: This paper describes a 70-year-old man with an incidental orbital mass detected by an imaging test and who later developed associated symptoms. The mass was diagnosed as neuromuscular hamartoma. Superior rectus muscle recession and inferior rectus muscle resection were performed in the right eye for hypertropia secondary to postoperative inferior rectus muscle palsy. Hypertropia in the right eye and diplopia improved after surgery, and regular follow-up is underway.
CONCLUSIONS: This is the first case of an incidentally detected orbital mass diagnosed by histologic examination as a neuromuscular hamartoma in an older patient whose proptosis progressed after a long period of inactivity.