Trilateral retinoblastoma--a case report.

A sporadic case of trilateral retinoblastoma in a male child of 20 months is described using clinical and imaging approaches. Attempts were made to find out a tumour marker by analysing human chorionic gonadotrophin (hCG), alpha-feto protein (AFP), carcinoembryonic antigen (CEA), and lactic dehydrogenase (LDH) in blood and cerebrospinal fluid (CSF). Only LDH was elevated in CSF and the rest were normal. Retinoblastoma gene could not be isolated in this patient. It is proposed that LDH in CSF should be analysed in patients with bilateral retinoblastoma who had normal brain scan initially. If LDH level in CSF is elevated, the patient should be periodically monitored by non-invasive imaging of the brain to detect intracranial tumour at an early stage.