The Course of Incidental Intraorbital Cavernous Hemangioma in a Patient with Myasthenia Gravis Treated with Cyclosporine: A Case Report
A 69-year-old woman had undergone a thymectomy at the age of 59 years because of a thymoma detected by routine chest X-ray examination. At the time of the thymoma detection, she had not shown any abnormal neurological symptoms. However, she has been suffering from symptoms such as moderate bilateral ptosis, severe diplopia, and muscle weakness after 10 years of thymoma operation, despite no recurrence of the thymoma. The affected muscles were the bilateral external ocular muscles, pharyngeal musculature, neck extensor muscle, deltoid, biceps, triceps, and iliopsoas. In particular, her left eye movement was limited in all directions. The diplopia developed at approximately the same time as the onset of the ptosis, and the extremity muscle weakness occurred during the 6 months following the onset of the external ocular symptoms. MG was diagnosed by the fluctuating symptoms, the waning detected in a repetitive nerve stimulation test on the median nerve, and positive test results for the acetylcholine receptor (AChR) antibody. The patient's quantitative MG score [] was of 24 points. After plasma exchange treatment, her qualitative MG score improved to 11 points. The AChR antibody titer at the initial visit was 250 μmol/l. The antibody titer decreased to 95 μmol/l after plasmapheresis (PP) treatment. However, improvement of the left external ocular movement (EOM) without ptosis was poor compared to the improvements in the right EOM, dysphagia, and limb muscles weakness. An orbital MRI was performed because the diplopia did not respond to PP or an edrophonium test, and revealed an intraorbital tumor of 3 cm in diameter. The tumor was diagnosed as an orbital cavernous hemangioma (OCH) by the imaging characteristics (fig. ). It was followed closely without treatment because the patient did not want surgical treatments for the tumor. She was treated with cyclosporine A (CsA) at concentrations from 100 to 150 ng/ml in order to improve the MG symptoms after PP treatment. Her diplopia began to improve thereafter over the course of 6 months. A follow-up MRI showed a reduction in the tumor size. The improvement of the left eye movement was paralleled by a significant reduction of the tumor rather than a change in the AChR antibody titer, although it was further reduced to 72 μmol/l by CsA therapy. On the other hand, continuing CsA therapy at concentrations of 100 to 150 ng/ml increased her systolic blood pressure to 160 mm Hg and decreased her glomerular filtration rate to 45 ml/min. In response to these adverse effect, the CsA concentration was controlled in the range from 75 to 100 ng/ml, which maintained blood pressure within the normal range and a glomerular filtration rate over 50 ml/min. After 7 years, a follow-up MRI was performed and the AChR antibody titer was 5.0 μmol/l. The CsA concentration was kept in the range from 75 to 100 ng/ml, and the tumor was maintained at a size that does not affect the EOM (fig. ).