Vitreous cytology as the only diagnostic evidence of central nervous system involvement in a patient with isolated leukemic infiltrative optic neuropathy

A 29-year-old female with treated acute lymphoblastic leukemia in remission presented with blurred vision and pain on movement of the right eye. On examination, visual acuity was 20/25 in the right eye and 20/20 in the left eye. Direct ophthalmoscopy revealed that the optic disc was swollen with peripapillary hemorrhage in the right eye. The rest of the clinical examination was within normal limits. Magnetic resonance imaging demonstrated enhancement of her right optic nerve. Lumbar puncture and bone marrow examination revealed no malignant cells. Only vitreous fluid cytology showed blast cells. Intravitreal injection of methotrexate was given, and repeated vitreous tapping was normal. The vision of her right eye remained 20/20 until 1 year later when optic disc and retinal vascular occlusion was noted. Her vision deteriorated to no light perception within 2 weeks, and optociliary shunt vessels occurred. Isolated disc swelling with positive vitreous cytology can be the first and only presentation of relapsed hematologic disorders. Infiltrative optic neuropathy should be considered in the differential diagnosis of optic disc edema. Vitreous tapping could be considered as the diagnostic procedure even if the results of lumbar puncture were negative.