Anterior diffuse retinoblastoma: mutational analysis and immunofluorescence staining

Abstract

Retinoblastoma is the most common primary intraocular tumor of childhood and may be heritable or occur sporadically. Anterior diffuse retinoblastoma is an uncommon variant that is thought to be sporadic. We describe a child with anterior diffuse retinoblastoma who presented with a pseudohypopyon. Genetic analysis showed a germline mutation of the RB1 allele that is potentially heritable. Immunofluorescence staining was positive for transforming growth factor beta and for vascular endothelial growth factor and negative for inducible nitric oxide synthase and for hypoxia inducible factor alpha in the tumor seeds, indicating acquisition of nonischemia-mediated survival factors of the tumor seeds in the aqueous humor.

Figure 1

The anterior chamber of the left eye contains a pseudohypopyon composed of white cells with associated neovascularization.

Figure 2

A, A fine-needle aspiration of the anterior chamber shows sheets of small, round, blue tumor cells. B, Some of these cells form rosettes (Wright-Giemsa, original magnification × 100).

Figure 3

Gross anatomic pathology of the enucleated eye. A, There is 360° tumor seeding of the space between the vitreous base and ciliary body. B and C, Areas of retinal hemorrhages with central white spots.

Figure 4

A, Tumor cells are present in the anterior chamber, trabecular meshwork, on the iris surface, and within the iris, where there is neovascularization (arrow). B, Tumor cells are present in the aqueous humor between the ciliary epithelium and the anterior hyaloidal surface of the vitreous humor (between arrows). C, Tumor within the retina (*) extends beneath a small vitreous detachment and anteriorly into the aqueous humor, where the vitreous base is breached (between arrows; hematoxylin-eosin, original magnifications × 100 [A] and × 25 [B and C]).

Figure 5

Immunostaining for tumor growth factor β (TGF-β; A and B) and immunostaining for vascular endothelial growth factor (VEGF; C and D). Counterstain for all (A through D) was propidium iodide. A, Immunofluorescent staining is positive in tumor cells in the anterior chamber for TGF-β. TGF-β staining was more intense in the anterior chamber tumor cells (A) as compared with the intraretinal tumor cells (B). There was moderate VEGF staining noted in both the anterior chamber tumor and intraretinal tumor cells (C and D) (original magnifications × 100 [A and C] and × 25 [B and D]).