RESUMO
This work aimed at studying the natural history of retinoblastoma [Rb] in our locality in addition to its potential histogenesis and prognostic markers .A series of [22] eyes with Rb of [19] patients were studied clinically [using indirect ophthalmoscopy with scleral indentation under general anaestheisa, ultrasonography and CT scanning] and histopathologically [using Hx and E stained sections, special stains and immunohistochemistry for neuron specific enolase [NSE]]. Metastatic disease work up was done during follow up period of at least 12 months.All cases were diagnosed in children less than 5 years of age [mean of 31 months for unilateral cases and 18 months for bilateral cases]. Male to female ratio was 1.2:1. Leukocoria and strabismus were most common mode of presentation [64%], [18%] respectively. Hx and E stained sections revealed that [75%] of eyes showed the trabecular pattern and [50%] showed the glomeruloid pattern. Homer Wright [H.W.] rosettes were seen in various degrees in all tumours [abundant in well differentiated tumour and few in poorly differentiated one]. Rb cells demonstrated varying degrees of positive or negative reaction to NSE, most Flexner-Winsterstenier [F.W.] and H.W. rosettes being positive and Fleurettes weakly positive or negative. Metastatic disease of retinoblastoma was related mainly to optic nerve invasion reaching the resection margin [75%] and poor tumour differentiation [80%].Regarding the natural history of retinoblastoma in this study, leukocoria and strabismus are the most common modes of presentation. Cases with bilateral lesions tend to present at younger age group. Immunohistochemical findings suggest that Rb is a primitive stem cell neuroectodermal tumour with capability for differentiation in both neural and neuroglial directions. The two main prognostic markers for metastatic disease are optic nerve invasion reaching the resection margin and poor tumour differentiation