Retinoblastoma with an unusual presentation in a child with polydactyly. Clinical associations and genetic implications

Abstract

Retinoblastoma is the most common intraocular malignancy of childhood. It may rarely present with white spots on the iris and pseudohypopyon. We report a case of an 11-month old child with polydactyly with this presentation of retinoblastoma. There was no positive family history of the disease. Investigations included anterior segment examination under anaesthesia, fundoscopy with scleral indentation, A- and B-scan ultrasound and MRI examination of the head. This was a Reese Ellsworth group 5 retinoblastoma with an indication for enucleation. Pathology reports of the enucleated globe showed choroidal and ciliary body invasion. Therefore, subsequent chemotherapy treatment was undertaken. The retinoblastoma gene is located in the long arm of chromosome 13. Almost all familial and bilateral cases carry the abnormal gene. In unilateral isolated retinoblastomas - as in our case - most patients do not have a germinal mutation, however, only DNA analysis can safely exclude that. We also discuss possible factors having a link to both polydactyly and retinoblastoma.