An 18-year-old female with unilateral painless vision loss.

An 18-year-old female presented with painless diminution of vision in the right eye for 2 months. She had best corrected visual acuity of 1/60 in the right eye and 6/6 in the left eye. Anterior segment examination and intraocular pressure were normal in both eyes. There were no cells in the anterior chamber or retrolental space. Fundus of the left eye was within normal limits. Fundus photograph and optical coherence tomography (OCT) of the right eye are given in Figures 1 and 2. Ultrasonogram (USG) of the right eye is given in Figure 3.

Figure 1

Fundus photograph of right eye

Figure 2

Optical coherence tomograph of the right eye

Figure 3

Ultrasonogram of the right eye

Questions

Describe the findings in Figures 1–3. What is the diagnosis?

What other investigations will you like to do to confirm the diagnosis?

Answers

Figure 1 shows a well-demarcated, slightly elevated reddish orange lesion near optic disc, measuring  3FNx013 disc diameters, with a round grayish-black membrane at its center. Associated subretinal bleed, subretinal fluid (SRF) and hard exudates are seen. OCT [Figure 2] shows SRF along with a hyper-reflective subretinal membrane nasal to the SRF suggestive of choroidal neovascular membrane (CNVM). USG of the right eye showed a highly reflective homogenous thickened choroidal lesion which persisted at low gain and showed acoustic shadowing [Figure 3]. The features are suggestive of choroidal osteoma with active CNVM in the right eye.

Other investigations included fundus fluorescein angiogram (FFA) and computed tomography (CT) scan of orbit. FFA showed early, irregular, diffuse mottled hyperfluorescence, and late staining suggestive of osteoma. The membrane over osteoma showed early hyperfluorescence increasing in size and intensity in the later phases suggestive of active CNVM [Figure 4]. CT scan showed a hyperdense (bone density) mass lesion at ocular coats near optic disc within the right eye.

Figure 4

Fundus fluorescein angiogram of the right eye

Discussion

Choroidal osteoma is a rare benign ossifying tumor first described by Gass et al.[1] Typically, it affects one eye of young healthy females, manifesting as a well-defined, slightly elevated, yellow-white or orange lesion in the peripapillary, or macular choroid. Poor vision occurs due to SRF with or without underlying CNVM,[2] or photoreceptor atrophy at fovea.[3] CNVM occurs in 31% eyes in 10 years.[4] Laser, photodynamic therapy (PDT), transpupillary thermotherapy, and surgical removal have been tried with mixed results in CNVM associated with osteoma. However, recently there has been a surge of literature on the efficacy of anti-vascular endothelial growth factors (VEGF) for the condition.[3] Our patient received three intravitreal bevacizumab (1.25 mg in 0.05 ml) injections in the right eye at one monthly intervals. The SRF, subretinal bleed and hard exudates resolved with the improvement of vision to 6/12 in the right eye at 7 months follow-up, without recurrences [Figure 5]. Khan et al.[3] suggest monthly intravitreal anti-VEGF therapy for extrafoveal tumors, until resolution followed by consolidation PDT. For subfoveal disease, monthly intravitreal anti-VEGF until control, followed by treat-and-extend approach has been suggested. PDT should better be avoided in subfoveal cases due to the risk of vision loss from photoreceptor loss due to decalcification of the tumor. However, optimal therapy is yet to be established for the condition. Intravitreal anti-VEGF agents promise to be critical in the management of such cases at present and in the future.

Figure 5

Fundus photograph of the right eye after three intravitreal bevacizumab injection

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Conflicts of interest

There are no conflicts of interest.