Unilateral retinocytoma associated with a variant in the RB1 gene

Abstract

Background: Retinocytoma is a rare benign retinal tumor associated with variants in the RB1 gene. Ophthalmoscopic features can include a translucent retinal mass, calcification, retinal pigment epithelial alteration and chorioretinal atrophy.

Methods: Detailed ophthalmological examinations were performed in a Chinese patient with retinocytoma and his daughter with bilateral retinoblastoma. Sanger sequencing was performed to detect RB1 genetic variants in the patient, his daughter and tumor tissue from his daughter.

Results: A 33-year-old man presented with poor vision and strabismus in the right eye since childhood. Fundus examination revealed a round yellow-white lesion stretching from the nasal side of the optic disc to the temporal periphery of the right eye. Sequencing result identified a reported variant (c.658C>G, p.Leu220Val) in the RB1 gene (NM_000321.2) of DNA extracted from peripheral blood of the patient and his daughter. The missense variant was also found in the tumor tissue from his daughter.

Conclusions: We report detailed clinical features and genetic analysis of a case with unilateral retinocytoma. Retinocytoma has a wide range of clinical phenotypes; genetic testing is therefore a useful tool for the diagnosis of atypical cases.

Keywords: RB1 gene; retinoblastoma; retinocytoma.

Figure 1

Fundus images of the patient. Color fundus photograph of right eye shows a large round‐shaped mildly elevated lesion with irregular yellowish‐white patches (arrows). The lesion is surrounded by chorioretinal and retinal pigment epithelial atrophy superior‐temporally and pigment proliferation (asterisk) in the inferior retina (a). The left fundus is normal (b).OCT images showing hyper‐reflective and thickened outer retina layers and thinned inner retina layers in right eye (c).OCT of the left eye is normal (d). B‐scan ultrasonography demonstrating a thick hyper‐reflective lesion (arrows) in right eye (e) and normal left eye (f)

Figure 2

ERG recordings of the patient. Mildly reduced rod and cone responses in right eye and normal responses in left eye were recorded