MULTIMODAL FUNDUS IMAGING OF OUTER RETINAL TUBULATIONS IN CHOROIDAL OSTEOMA PATIENTS

To evaluate the morphological findings of outer retinal tubulations (ORTs) shown on multimodal imaging modalities in patients with choroidal osteoma.

Nineteen eyes of 17 patients with choroidal osteoma underwent full clinical and imaging assessments. Color fundus photography, spectral-domain optical coherence tomography (OCT), and en face OCT were used to identify and detect the characteristics of ORT structures, including the shape, configuration, location, and distribution in the fundus. Optical coherence tomography angiography was implemented as an assist to differentiate tumor's feeder vessels from choroidal neovascularization. The correlations between age, gender, tumor features, best-corrected visual acuity at baseline, OCT characteristics, and the presence of ORTs were analyzed.

Outer retinal tubulations were identified in five eyes (26.3%). All were located at the decalcified region of the tumor where the choroidal vessels, retinal pigment epithelium, and overlying outer retinal structures were considerably disrupted to varying degrees. With spectral-domain OCT, the ORTs appeared as one or multiple, round or ovoid, hyporeflective lumens with hyperreflective borders confined to the outer nuclear layer, sometimes with hyperreflective luminal content (four eyes, 80%). In one eye, ORTs were found at the focal choroidal excavation. On en face OCT, these tubulations exhibited different shapes, including a dendritic pattern in two eyes, a tube-like pattern in one eye, a circular pattern in one eye, and a hairpin pattern in one eye. Simultaneous OCT angiography imaging demonstrated that the area of choroidal neovascularization was underneath ORT in one eye and very close to ORT in two eyes. The ORTs of three eyes were above or adjacent to tumor's rich feeder vessels. Statistically, age (P = 0.007), greatest tumor linear dimension (P = 0.003), total tumor area (P = 0.002), decalcification area (P = 0.000), and the presence of intraretinal fluid (P = 0.01) and retinal pigment epithelium alterations (P = 0.038) within the foveola and central 1-mm region of patients with ORT were significantly different from those of patients without ORTs.

The results of this study suggest that age, the greatest tumor linear dimension, total tumor area, decalcification area, and the presence of intraretinal fluid and retinal pigment epithelium alterations within the foveola and central 1-mm region might be risk factors for ORT formation. Spectral-domain OCT combined with en face OCT provides comprehensive imaging information for ORTs in choroidal osteoma.