Detection and Intraretinal Localization of an 'Invisible' Retinoblastoma Using Optical Coherence Tomography.

PURPOSE: To report the use of handheld spectral-domain optical coherence tomography (HHSD OCT) to identify and define the intraretinal location of a small retinoblastoma that was not detectable by indirect ophthalmoscopy.

METHODS: This is a retrospective case report of a tumor identified with HHSD OCT in a single patient.

RESULTS: A 7-week-old male was diagnosed with unilateral group E retinoblastoma in the right eye. An enucleation was completed successfully with histopathologic confirmation of the diagnosis. The normal left eye was monitored for the development of retinoblastoma, and 10 weeks after diagnosis, three new small retinoblastomas were noted in the posterior pole. Identification of the smallest of the three tumors was facilitated by HHSD OCT; it was adjacent to the optic nerve head, and involved the outer nuclear layer, outer plexiform layer, and inner nuclear layer, with the inner retina draping over the tumor.

CONCLUSION: HHSD OCT can aid the ocular oncologist in the identification of very small retinoblastomas before they are visible to the eye, which allows for earlier and potentially vision-sparing treatment of these lesions. Additionally, the ability to identify these very small tumors and to localize them anatomically within the retinal layers may aid in our understanding of retinoblastoma tumorigenesis.