Uveitis masquerade syndrome as a presenting form of diffuse retinoblastoma

A 3-year-old boy presented with an intermediate uveitis. Complete ophthalmic exam, ocular ultrasonography, magnetic resonance imaging and computerized tomography of the orbit were inconclusive. Determination of the aqueous humor/serum rate of Lactate dehydrogenase (LDH) was the key for the diagnosis of a diffuse retinoblastoma. A masquerade syndrome is the initial presentation in 1-3% of retinoblastomas. Aqueous humor punction is contraindicated in patients with retinoblastoma but it might be the only way to achieve a correct diagnosis in these difficult and very unusual cases: enzymatic assays such as LDH offer a good sensitivity and specificity for the diagnosis of these patients.