Optic nerve breast metastasis mimicking meningioma

Purpose: We report on an optic nerve breast metastasis masquerading initially as a central retinal vein occlusion and later as an optic nerve meningioma. Methods: A 60-year-old female presented with a left central retinal vein occlusion (CRVO). She represented 7 months later with left upper ptosis, proptosis and painful rubeotic glaucoma. Computed tomography (CT) and magnetic resonance imaging suggested an optic nerve meningioma. On referral to the regional orbital unit, a mild left external ophthalmoplegia was noted and, in view of previous right mastectomy and chemotherapy 3 years earlier, the left optic nerve was biopsied simultaneously with left enucleation of her painful eye. Results: Histopathology showed infiltration of the optic nerve and meningeal sheath spreading into the subretinal space and vitreous by malignant epithelial cells, consistent with breast origin. Further CT imaging and bone scans revealed no other metastases. Single field left orbit radiotherapy of 20 Gy was given in five fractions and Arimidex (Zeneca Pharmaceuticals, Cheshire, England) was commenced with the cessation of tamoxifen. The patient was also given an ocular prosthesis. Sadly, she lost vision in her other eye due to retrograde malignant invasion of her optic chiasm and died 6 weeks later. Conclusions: Orbital and choroidal metastases are relatively common but isolated optic nerve metastases are extremely rare. Progressive infiltration of the nerve is likely to enhance CRVO ischaemia and resultant rubeotic glaucoma. In the diagnosis of CRVO, proptosis or external ophthalmoplegia, the presence of pre-existing malignant disease should raise concerns, as delay in diagnosis may affect outcome, particularly if the metastases are sensitive to pharmacological therapy.