Retinoblastoma: association between high-risk histopathological and clinical features of primary enucleated eyes at Muhimbili National Hospital

Abstract

Introduction: Retinoblastoma is the commonest primary intraocular malignancy in children. Diagnosis is established clinically after examination under anaesthesia. Primary enucleation is indicated in an advanced disease in unilateral group D and group E eyes. Histopathology confirms the presence of histopathological high risk features which indicate poor prognosis hence need for further treatment. Literatures have highlighted clinical features which may relate to the presence of histopathological high risk features on enucleated eyes. Aim: To associate the clinical and histopathological high risk features of primary enucleated eyes with retinoblastoma at Muhimbili National Hospital. Methodology: A hospital based descriptive cross sectional study done in ophthalmology and histopathology unit at Muhimbili National Hospital. Previous data from January 2018 to June 2020 was obtained and consecutive sampling was done to recruit a total of 66 participants from January 2018 to December 2020. Interviews, examination under anaesthesia and histopathology of all study eyes was done. Data were captured by questionnaire and analyzed by statistical package for social sciences version 23. Mann Whitney test and independent T test tested median and mean differences. Chi squire and Fishers test tested the association which was significant when p value was <0.05. Mean, median, frequency tables, histograms, pie charts and statistical tables were used to summaries continuous and categorical data. Results: Total of 66 (38.5%) patients were recruited among patients with retinoblastoma who were attended during the study period. The median intraocular pressure and mean horizontal cornea diameter were 28.5mm Hg and 11.8SD0.93 respectively. The most prevalent features during examination under anaesthesia were dilated pupil and larger tumor size in 72.7% each. Histopathological high risk features were seen in 64% predominated by massive choroidal involvement in 53% of the eyes. Massive necrosis and poor tumor differentiation each were seen in 40.9% of the eyes. The median intraocular pressure was statistically higher in patients with high risk histopathological features (HHRF) than those without HHRF. Place of residence, duration of symptoms, horizontal cornea diameter, high intraocular pressure, shallow anterior hamber depth, iris heterochromia, dilated pupil, poor tumor differentiation and extensive necrosis were related to histopathological high risk features with a p values of less than 0.05. Conclusion and recommendation: The proportion of patients with retinoblastoma undergoing primary enucleation is still low. Nearly 2 out of 3 eyes have histopathological high risk feature. Massive choroidal involvement was the most identified histopathological high risk feature. A place of residence, duration of symptoms, dilated pupil, high intraocular pressure, iris heterochromia, shallow anterior chamber, poor differentiation and extensive necrosis were associated with the presence of histopathological high risk feature. Strategies to increase awareness on retinoblastoma to the general public are emphasized. Tertiary care for retinoblastoma should be established in the level of zonal hospital to reduce patients coming late to the hospital