Accelerated growth of an orbital schwannoma during pregnancy.

An incidentally diagnosed unilateral orbital mass in a 34-year-old woman grew at an accelerated rate during pregnancy with deterioration of visual function. Removed early after delivery by a transcranial approach, the tumor was histologically diagnosed as a richly vascularized cystic schwannoma containing red blood cell components. The accelerated tumor growth was attributed to intratumoral hemorrhage. Although acoustic schwannomas have been reported to enlarge during pregnancy, this phenomenon has only been described once for orbital schwannomas. Because this type of tumor may enlarge during pregnancy and threaten visual function, surgery should not be delayed.