Elevated lactic acid dehydrogenase in aqueous humor in an eye without retinoblastoma.

A 14-month-old boy had a microphthalmic left eye. An anterior chamber paracentesis was performed six days after examination under anesthesia. Lactic acid dehydrogenase (LDH) level in the aqueous humor was 1,158 mu and was 202 mu in the serum. The aqueous humor/serum LDH ratio was 5.73. This eye was eventually enucleated and found to have retinal dysplasia and diffuse hemorrhagic necrosis. There was no eividence of retinoblastoma. The elevated LDH level in aqueous humor was probably secondary to the ocular tissue necrosis and hemorrhage. This false-positive result emphasizes the limitation of using the aqueous humor/serum LDH ratio to distinguish eyes with retinoblastoma from those without retinoblastoma.