Retinoblastoma major review with updates on Middle East management protocols

Abstract

Many advances in the field of management of retinoblastoma emerged in the past few years. Patterns of presentation of retinoblastoma in the Middle East region differ from Western community. The use of enucleation as a radical method of eradicating advanced disease is not easily accepted by patient's family. We still do see stage E, failed or resistant retinoblastoma and advanced extraocular disease ensues as a result of delayed enucleation decision. In this review, we discuss updates in management of retinoblastoma with its implication on patients in our part of the world. Identifying clinical and high risk characteristics is important prognostically and are discussed for further management of retinoblastoma cases.

Keywords: Classification; Histopathology; Middle East; Retinoblastoma; Staging.

Figure 1

Growth cycle: most cells of the body are in G0 or quiescent stage. When they start cell division, they pass through G1, S, G2 and M phases. Retinoblastoma protein (Rb) in its active hypophosphorylated form acts on the checkpoint from G1 to S phase to ensure flawless DNA replication.

Figure 2

Inactivation of Rb protein by hyperphosphorylation results in uncontrolled cell replication.

Figure 3

Hereditary or genetic mutation starts in a sperm “first hit” (red chromosome in the sperm). This results in a zygote with loss of one allele of RB gene. A second hit (arrow) occurs in a retinoblast resulting in tumor formation. All cells of the body carry a hemizygote state of RB.

Figure 4

Hereditary retinoblastoma diagnosed in the sibling at age 2 weeks OS. Child underwent chemoreduction with focal therapy. B: initial good response after laser transpupillary thermotherapy. C: Tumor recurrence. D: tumor ablation following Ruthenium-106 plaque application. Tumor controlled at 60 months follow up.

Figure 5

High risk factors with retinoblastoma. (A) Gross section showing massive choroidal invasion (>3 mm) with optic nerve invasion. (B) Photomicrograph showing scleral invasion (block arrow) with estrascleral invsion (asterisk) (H&E. original magnification 100×). (C) Optic nerve section showing malignant round blue cells invasion beyond lamina cribrosa (arrow).

Figure 6

(A) Vitreous seeds and inferonasal tumor recurrence following chemofocal therapy and external beam radiation for unilateral sporadic retinoblastoma. (B) Tumor and vitreous seeds control following 3 monthly injection of intraophhtlamic artery melfalan.

Figure 7

Ophthalmic artery occlusion with severe choroidal RPE mottling following a second injection of ophthlamic artery melfalan.