Diagnosis of Retinoblastoma
A thorough clinical evaluation with careful attention to details, aided by ultrasonography B-scan helps in the diagnosis.10 Computed tomography and magnetic resonance imaging are generally reserved for cases with atypical manifestations and diagnostic dilemma and where extraocular or intracranial tumor extension is suspected. 10
A child with suspected retinoblastoma necessarily needs complete ophthalmic evaluation including a dilated fundus examination under anaesthesia.10 The intraocular pressure is measured and the anterior segment is examined for neovascularization, pseudohypopyon, hyphema, and signs of inflammation 10
Bilateral fundus examination with 360 degree scleral depression is mandatory. Direct visualization of the tumor by an indirect ophthalmoscope is diagnostic of retinoblastoma in over 90% of cases. 21 RetCam is a wide-angle fundus camera, useful in accurately document ing retinoblastoma and monitoring re sponse to therapy (Figure 12).Ultrasonography B-scan shows a rounded or irregular intraocular mass with high internal reflectivity representing typical intralesional calcification (Figure 13). 10 Computed tomography delineates extraocular extension and can detect an associated pinealoblastoma (Figure 14).10 Magnetic resonance imaging is specifically indicated if optic nerve invasion or intracranial extension is suspected. 10On fluorescein angiography, smaller retinoblastoma shows min imally dilated feeding vessels in the arterial phase, blotchy hyperfluorescence in the venous phase and late staining (Figure 15). 10
- Figure 12. RetCam, a wide-angle digital fun dus camera and image archival system helps in documentation and assessment of tumor regression on follow-up
- Figure 13. Ultrasonography B-scan showing multifocal retinal tumors
- Figure 14. Computed tomography scan shows pinealoblastoma
- Figure 15. Fundus fluorescein angiography in retinoblastoma in the early phase shows blotchy hyperfluorescenc
Classification of Retinoblastoma
An ideal classificationsystem for retinoblastoma should include two components: grouping and staging. Grouping is a clinical system of prognosticating organ salvage while staging prognosti cates survival.22
The Reese Ellsworth classification was introduced to prognosticate patients treated with methods other than enucleation. This classification was devised prior to the widespread use of indirect ophthalmoscopy and focal measures of management of retino blastoma and mainly pertained to eye salvage with external beam radiotherapy. Although the Essen classification addressed some of the shortcomings of Reese Ellsworth classification, it is considered too complex.
Further, none of the older systems of classification had been designed to prognosticate chemoreduction, the current favored method of retinoblastoma management. The new International Classification of Intraocular Retinoblastoma is a logical flow of sequential tumor grading that linearly correlates with the outcome of newer therapeutic modalities (Table 2).23, 24
Table 2:International Classification of Intraocular Retinoblastoma Courtesy Carol L Shields, MD, Wills Eye Institute, Philadelphia, PA, USA
The new International Staging system is the first such for retinoblastoma and incorporates five distinct stages (Table 3).25 Staging is based on collective information gathered by the clinical evaluation, imaging, systemic survey and histopathology.
Management of Retinoblastoma
The primary goal of management of retinoblastoma is to save life. Salvage of the organ (eye) and function (vision) are the secondary and tertiary goals respectively. The management of retin oblastoma needs a multidisciplinary team approach including an ocular on cologist, pediatric oncologist, radiation oncologist, radiation physicist, genetist and an ophthalmic oncopathologist. The management strategy depends on the stage of the disease – intraocular retinoblastoma, retinoblastoma with high-risk characteristics, orbital retino blastoma and metastatic retinoblas toma.
Management of retinoblastoma is highly individualized and is based on several considerations - age at presentation, laterality, tumor location, tumor stag ing, visual prognosis, systemic condition, family and societal perception, and, to a certain extent, the overall prognosis and cost-effectiveness of treatment in a given economic situation .
