Background: Enterogenous cysts of the central nervous system are rare congenital tumors with a single layer of mucin-secreting epithelial cells resembling gastrointestinal epithelium. The tumor is located most commonly at lower cervical and cervicothoracic spinal levels; only 22 intracranial cases have been reported. To the authors knowledge, this entity has not been described in the orbit.
Methods: A 23-year-old woman with painful loss of vision and ophthalmoplegia in the left eye was treated with oral and intravenous corticosteroids for presumed orbital inflammation. After a cystic lesion in the left orbital apex was demonstrated on computed tomographic scan and magnetic resonance imaging, various diagnoses, including optic nerve tumor, granulomatous inflammation, lymphoma, vascular anomaly, and pseudotumor, were considered until transcranial biopsy established the correct diagnosis. The tumor subsequently recurred twice.
Results: More than 3 years after the last recurrence, the patient has no pain but had unilateral optic atrophy, significant visual field loss, limited motility, and an anesthetic cornea in the left eye.
Conclusion: The diagnosis of enterogenous cyst is difficult without adequate biopsy because the radiologic and clinical presentation of this rare tumor may be confused with other lesions. Previous attempts to explain intracranially placed enterogenous cysts offer no explanation for an orbital occurrence nor do they adequately describe a mechanism for an intracranial location in general. An embryologically based explanation that takes into account the occurrence of this entity from the caudal to rostral extent of the neuraxis is described. This theory suggests that the orbit is the most rostral possible location for an enterogenous cyst.