Choroidal osteoma is a rare intraocular tumor, composed of mature calcified bone and typically found in young adult women.1,2 Long-term findings of this benign tumor include tumor growth in 51%, tumor decalcification in 46%, development of choroidal neovascularization in 31%, and visual acuity of 20/200 or worse in 56%.3 Tumor decalcification usually occurs spontaneously after many years.3 Laser photocoagulation for choroidal neovascularization can induce focal tumor decalcification.4 Decalcification is important because this minimizes further growth of the tumor at that site and could protect the fovea from tumor involvement and visual loss.3 We report photodynamic therapy to an extrafoveal choroidal osteoma that induced decalcification and resorption of bone, leaving a small area of subretinal fibrosis.
An asymptomatic 25-year-old woman had a juxtapapillary choroidal osteoma in her right eye, measuring 3 mm in diameter. Her visual acuity was 20/20 in each eye. An overlying subretinal hemorrhage was present (Figure 1). Ultrasonography showed an echodense mass consistent with calcium. Observation was advised.
Findings before photodynamic therapy: a small juxtapapillary choroidal osteoma with overlying subretinal hemorrhage (A), ultrasonography confirmed the calcified choroidal tumor with acoustic shadowing (B), and optical coherence tomography showed slight elevation of the mass (between arrows) with minimal light shadowing and an intact photoreceptor layer (C).
On follow-up at 6 and 18 months, the stable mass showed persistent hemorrhage, suggesting choroidal neovascularization. Photodynamic therapy to the entire osteoma was performed using a single 83-second laser spot at 689 nm (50 J/cm2) coupled with intravenous verteporfin, 6 mg/m2. The hemorrhage resolved by 1 month. The bone remained intact until 9 months, when there was complete disappearance of the osteoma, leaving a 2-mm region of subretinal fibrosis and retinal pigment epithelial hyperplasia (Figure 2).
Findings 9 months after single photodynamic therapy: the hemorrhage and mass were completely resolved, leaving only subretinal fibrosis and retinal pigment epithelial hyperplasia (A); ultrasonography showed no evidence of calcium (B); and optical coherence tomography showed the subretinal tissue with shadowing from retinal pigment epithelial hyperplasia and transmission through fibrosis (between arrows) (C).
The reasons for vision loss from choroidal osteoma include photoreceptor degeneration, subfoveal fluid, and subfoveal hemorrhage from related choroidal neovascularization. In an analysis of 74 eyes with choroidal osteoma, good visual acuity (20/20-20/40) was found in 24 of 30 eyes (80%) without foveolar involvement of tumor compared with 20 of 44 eyes (45%) with foveolar involvement.3 In addition, tumors with decalcification showed little or no growth in the direction of the decalcification.3 Based on these observations, inhibition of tumor growth into the foveola by stimulating decalcification within the entire tumor or at least the portion of the tumor nearest the foveola could protect long-term visual acuity.
Decalcification of choroidal osteoma appears as an atrophic flat bed of retinal pigment epithelium and choroid. Decalcification typically occurs spontaneously and initiates in the central part (37%), peripheral part (48%), or diffusely (15%) within the osteoma.3 Progressive decalcification occurs slowly and occupies approximately 40% of the tumor by 10 years.3 Laser photocoagulation can induce focal tumor decalcification.2,3 In this report, we observed that photodynamic therapy caused decalcification and involution of the entire tumor. This finding is important because photodynamic therapy could be a therapeutic modality for choroidal neovascularization and induction of decalcification of extrafoveal osteoma to prevent tumor growth into the foveola.
These results should not be extrapolated to subfoveal choroidal osteoma.3 It is speculated that decalcification of subfoveal choroidal osteoma could result in worse visual acuity because of loss of retinal pigment epithelium and choroidal perfusion.
Correspondence: Dr C. L. Shields, Ocular Oncology Service, Wills Eye Hospital, 840 Walnut St, Ste 1440, Philadelphia, PA 19107 (email@example.com).
Author Contributions: Dr C. L. Shields had full access to all the data in the study and takes responsibility for the integrity and accuracy of the data analysis.
Financial Disclosure: None reported.
Funding/Support: This study was supported by the Retina Research Foundation of the Retina Society, Cape Town,South Africa (Dr C. L. Shields); Mellon Charitable Giving from the Martha W. Rogers Charitable Trust, Philadelphia, Pennsylvania (Dr C. L. Shields); the LuEsther Mertz Retina Research Foundation, New York, New York (Dr C. L. Shields); a donation from Michael, Bruce,and Ellen Ratner, New York (Drs C. L. Shields and J. A. Shields); the Eye Tumor Research Foundation, Philadelphia (Drs C. L. Shields and J. A. Shields); and the Paul Kayser International Award of Merit in Retina Research, Houston, Texas (Dr J. A. Shields).
Shields CL, Materin MA, Mehta S, Foxman BT, Shields JA. Regression of Extrafoveal Choroidal Osteoma Following Photodynamic Therapy. Arch Ophthalmol. 2008;126(1):135-137. doi:10.1001/archopht.126.1.135