Purpose
To describe the morphologic features of calcified and decalcified choroidal osteomas using multimodal imaging and correlate these findings with a previous histopathologic study.
Design
Retrospective observational case series.
Methods
Three patients with choroidal osteoma underwent complete ophthalmologic examination, fundus photography, and multimodal fundus imaging, including Fourier-domain optical coherence tomography (FD-OCT) and blue-light fundus autofluorescence (bAF).
Results
FD-OCT imaging of calcified tumors revealed a distinctive latticework pattern of reflectivity resembling the spongy bone structure seen histopathologically. On bAF the fluorescence was relatively well preserved overlying calcified tumors. In decalcified areas 2 patterns of reflectivity were identified: the first consisted of areas of relative hyperreflectivity with a lamellar appearance while the second was characterized by heterogeneous, hyperreflective, mound-like irregular areas associated with some posterior optical shadowing. Decalcified tumor areas had reduced overall fluorescence on bAF.
Conclusion
FD-OCT demonstrated different reflectivity patterns in both calcified and decalcified portions of the choroidal osteoma, which may correspond to different stages of tumor evolution. A distinctive latticework pattern of reflectivity similar to spongy bone was seen in calcified tumors. These observations improve our knowledge of the in vivo structure of choroidal osteomas and may have implications for the diagnosis and management of this tumor.
Choroidal osteoma is a benign osseous tumor of the choroid that, unlike other intraocular ossifications, usually affects healthy eyes. It is unilateral in approximately 80% of cases and more often affects young female subjects. Clinically it appears as yellow-white to orange-red lesions, depending on the degree of thinning and depigmentation of the overlying retinal pigment epithelium (RPE). Because of the calcific composition, choroidal osteomas present with high reflectivity and acoustic shadowing on ultrasonography, and appear as hyperdense plaques at the level of the choroid on computed tomography. On time-domain optical coherence tomography (TD-OCT) irregular plate-like high-signal-intensity areas as well as photoreceptor loss were observed over decalcified regions of the tumor. Limitations of TD-OCT technology, however, precluded adequate imaging of the choroidal vascular compartment.
Recent advances in OCT technology, such as the development of new light sources and a novel high-speed OCT technique called spectral OCT, which is based on “Fourier-domain” (FD) detection, have allowed higher axial resolution imaging with improved sensitivity and increased measurement speed to more than 50 times compared with TD-OCT instruments. Moreover, the integration of FD-OCT findings with data from relatively new imaging modalities, such as blue-light fundus autofluorescence (bAF), carries the potential for an expanded interpretation of fundus imaging findings. Herein, we describe the morphologic features in patients with choroidal osteoma undergoing multimodal fundus imaging, with particular interest in findings obtained on FD-OCT imaging and bAF.
Methods
Three patients with choroidal osteoma who had undergone multimodal fundus imaging from July 1, 2009 to December 31, 2010 were identified through a review of medical records at the Macular Imaging and Treatment Division of the Hospital de Olhos de Araraquara (Araraquara, São Paulo, Brazil). The diagnosis was based on the presence of a yellow-white to orange-red mass deep to the RPE with well-defined margins and bone density on ultrasonography. All participants underwent FD-OCT and bAF imaging on commercially available equipment (Spectralis HRA+OCT, Heidelberg Engineering Inc, Heidelberg, Germany). The bAF documentation was obtained with an excitation wavelength of 488 nm and the emitted light detected above 500 nm, using the high-resolution mode with the ART (automatic real time) mean module set at 25 frames and “normalized” function on.
Results
Patient characteristics and tumor features are summarized in the Table and Figure 1 . Four eyes of 3 patients (2 female and 1 male) were included. One eye of a patient with bilateral choroidal osteoma was excluded because of significant vitreous opacities. Fluorescein angiography was performed in Patient 1 ( Supplemental Figure , available at AJO.com ).
| Patient Number, Sex, Age (y) | BCVA | Location and Stage of Tumor | ||
|---|---|---|---|---|
| OD | OS | OD | OS | |
| 1, F, 16 | 20/125 −1 | 20/20 −2 | Juxtapapillary/macular; calcified | NA |
| 2, F, 61 | 20/640 | 20/125 | Juxtapapillary/macular; centrally decalcified, peripherally calcified | Juxtapapillary/macular a |
| 3, M, 36 | 20/320 +1 | 20/125 | Juxtapapillary/macular; decalcified | Juxtapapillary/macular; decalcified |
In calcified areas, we identified on FD-OCT areas with a latticework reflective pattern within the choroid ( Figure 2 , Top) and associated reflective signals corresponding to large vessels located mostly between the calcified tumoral tissue and the RPE-Bruch reflective complex ( Figure 3 , Top). In some regions, an apparent hyperreflective line separating the calcified tumoral tissue and adjacent, presumably unaffected, choroid was observed ( Figure 2 , Middle). The retinal layers overlying calcified tumoral tissue presented relatively preserved reflectivity on FD-OCT, with the exception of the foveal region of Patient 1, who had choroidal neovascularization in the past ( Figure 2 , Bottom). A thin hyporeflective space was frequently identified underneath (ie, external to) the RPE–Bruch reflective complex in calcified tumoral regions ( Figure 3 , Middle). Given that calcified regions presented preserved fluorescence on bAF ( Figure 1 , Top left and right), this hyporeflective space may correspond to remaining choriocapillaris.
In decalcified areas, we identified 2 different reflective patterns on FD-OCT, which were both associated with complete disorganization of the adjacent outer retina signaling. The first consisted of areas of relative hyperreflectivity with a lamellar appearance (external to the RPE–Bruch reflective complex) ( Figures 3 and 4 , Bottom), while the second was characterized by heterogeneously, hyperreflective, mound-like irregular areas associated with some posterior optical shadowing ( Figure 4 , Top), which occasionally were located above (ie, internal to) the Bruch membrane ( Figure 4 , Middle). In lamellar-appearing regions, with few exceptions, no reflective signals from choroidal vessels could be identified ( Figures 3 and 4 , Bottom). Moreover, an arborescent hyporeflective vertical structure was identified in the deeper part of the lamellar-appearing region in Patient 2 ( Figure 3 , Bottom), and may correspond to a posterior ciliary vessel penetrating the sclera. On bAF documentation, decalcified tumor areas presented areas of no fluorescence alternating with areas of mild residual fluorescence ( Figure 1 , Top right and Bottom left and right).
