Carcinoid metastasis to extraocular muscles: case reports and review of the literature.

Carcinoid tumors are slow growing, low-grade malignant neoplasms that are believed to originate from neuroendocrine cells, usually in the gastrointestinal mucosa. Metastasis of carcinoid tumor to the orbit is a rare occurrence. When metastasis does occur, the choroid is the most common ocular structure involved. We report two cases of unique involvement of extraocular muscles.