Retroperitoneal teratoma causing ptosis: A case report.

The present study reports the case of a patient who had undergone unsuccessful hormone therapy for ocular myasthenia gravis 14-years prior to the current presentation. The diagnosis of ocular myasthenia gravis was once again confirmed by a neostigmine test and repeat nerve stimulation study. Computed tomography scans in an external institution revealed a retroperitoneal cystic tumor with calcification above the left adrenal gland. The tumor was removed via a transperitoneal laparoscopic resection and was diagnosed as a mature cystic teratoma upon pathological examination. A teratoma is a common form of germ cell tumor, but primary teratomas of the retroperitoneum are quite rare in the adult population. Post-operative observation of the patient showed resolution of the ptosis and improved movement of the eyeballs. The potential mechanism was unclear, but the patient's teratoma was mature and may have contained myoid cells with antigenicity for anti-acetylcholine receptor (anti-AchR), as has been established in the thymus. Therefore, the anti-AchR antibody may have been involved.