CHOROIDAL OSTEOMA SHOWS BONE LAMELLA AND VASCULAR CHANNELS ON ENHANCED DEPTH IMAGING OPTICAL COHERENCE TOMOGRAPHY IN 15 EYES

Purpose: To describe enhanced depth imaging optical coherence tomography findings of choroidal osteoma. Methods: Retrospective, observational case series of 15 eyes with choroidal osteoma imaged with EDI-OCT. Results: The mean age at presentation was 27 years. There were 10 women and 3 men. The visual acuity ranged from 20/20 to hand motion, with reduced visual acuity secondary to photoreceptor loss in the foveola (n = 5) or subfoveal fluid (n = 1), and additional choroidal neovascular membrane (n = 3). The mean basal tumor diameter was 8.0 mm, and ultrasonographic thickness was 1.5 mm. Using enhanced depth imaging optical coherence tomography, the mean tumor thickness was 589 mm when compared with a matched choroidal region in the unaffected eye of 247 mm (138% increased thickness) (P = 0.009). The tumor surface topography was classified (ultrasonography vs. enhanced depth imaging optical coherence tomography) as flat (87 vs. 13%), dome (13 vs. 40%), or undulating (0 vs. 47%). On enhanced depth imaging optical coherence tomography, unique features included horizontal lamellar lines (presumed bone lamella) (n = 15, 100%) and hyperreflective horizontal lines (presumed cement lines) (n = 8, 53%). Other features included horizontal tubular lamella with optically empty center (presumed Haversian canals or vascular channels) (n = 9, 60%), vertical tubular lamella (presumed Volkmann canals or vascular channels) (n = 2, 13%), and speckled regions (presumed compact or small trabecular bone) (n = 6, 40%). Of the nine eyes with subfoveolar osteoma, the tumor was completely ossified (n = 4), partially deossified (n = 2), or completely deossified (n = 3). Photoreceptor thinning/atrophy was found in all five eyes with deossified osteoma, whereas intact photoreceptor appearance was noted in the four eyes with ossified subfoveal osteoma. Conclusion: Enhanced depth imaging optical coherence tomography reveals characteristic surface topography of choroidal osteoma as dome or undulating (87%) with unique intrinsic features of horizontal lamellar lines (100%), horizontal (60%) or vertical (13%) tubules, and speckled regions (40%). Photoreceptor loss was evident in every case of tumor deossification.