Diagnosis of retinoblastoma

Purpose Retinoblastoma is the most frequent malignant intra ocular tumors in childhood. The incidence is one out of 15000 to 18000 births. The median age at diagnosis is 24 months for unilateral and 12 months for bilateral. The genetic predisposition is autosomal do Methods In 1971 Knudson made the hypothesis that 2 genetic alterations in the same retinal cell were necessary. In bilateral disease there is one germline and one somatic mutation and in unilateral non hereditary, 2 somatic mutations. The Rb1gene is located on chromosome 13 q 1‐4 . The Rb 1 protein is a pocket protein involved in the cell cycle regulation Results Most frequent symptoms are leukocoria and strabismus Later symptoms include heterochromia iridis,rubeosis, buphtalmia, pseudo hypopion, uveitis, inflammatory pseudo tumor and exophtalmia. Diagnosis of retinoblastoma is made by fundus examination. Imaging of the orbits and brain should be performed using MRI if possible. Ultrasonography with B and A scan is also useful as well as the use of Retcam . Differential diagnosis is sometimes easy when there is colobomas ,persistance of hyperplastic primary vitreous ,hamartomas or astrocytomas It can be difficult in cases of advanced Coats disease or when there is diffuse infiltrating retinoblastoma. Conclusion We have made a retrospective study on patients sent for suspicion of retinoblastoma in our institute from January 2003 to December 2005 If we compare this serie to the serie published in the literature we can say that the pourcentage of well diagnosed retinoblastoma is improving. We have found 16% of wrong diagnostics. There was 30% in the serie of Balmer in 1988 and 42% in the serie of Shields in 1991. The most frequent differential diagnosis reported in all series is Coats disease