Bilateral Choroidal Osteoma Associated with Optic Neuritis in Behçet’s Disease

Introduction

Choroidal osteoma is a rare, well-defined benign tumor, which is typically unilateral and is found in healthy young individuals.¹ The tumor predominantly occupies the full thickness of the peripapillary choroid and the pathogenesis of this bone formation remains uncertain.¹ Characteristic ophthalmoscopic features, B-scan ultrasonography and computed axial tomography (CT) may help to achieve the diagnosis by showing calcified plaque at the level of the choroid.² Several atypical clinical presentations have been reported¹ but the association with ocular inflammation is extremely rare.^3,4 This report describes the onset and progression of a bilateral asymmetric choroidal osteoma following recurrent episodes of optic neuritis as the initial symptom for Behçet’s disease. Furthermore, we describe the 3-dimensional optical coherence tomographic features in the posterior pole of this uncommon pathology.

Case Report

A 36-year-old woman was referred with a two-month history of bilateral anterior uveitis and optic neuritis in her right eye. Demyelinizing disease of the central nervous system had been ruled out by cranial and orbital magnetic resonance imaging 1 year before. At presentation, visual acuity in her right eye was 20/200 and slit-lamp examination showed +2 cells in the anterior chamber. Ophthalmoscopy revealed +1 cells in vitreous, peripapillary choroidal infiltrates associated with swelling and loss of contour of the optic disk suggesting optic neuritis (Fig. 1A). The patient also presented oral ulcers and cutaneous nodules on her arms and legs fulfilling the criteria of Behçet’s disease.⁵ HLA-B51 antigen was positive. Systemic treatment with oral cyclosporine A (5 mg/kg/day) and oral prednisone (0.5 mg/kg/day) was initiated in association with topical steroids and mydriatics in the right eye with control of anterior chamber inflammation. Despite systemic treatment with cyclosporine A and prednisone, the patient developed bilateral anterior uveitis associated with neuroretinitis—optic neuritis with macular involvement—and a well-circumscribed peripapillary choroidal infiltration in the right eye 2 years later (Fig. 1B). Fluorescein angiography identified hyperfluorescence of the optic disk and a choroidal peripapillary infiltration area (not shown). One year later, after recurrence of anterior uveitis associated with optic disk inflammation in her left eye, we observed peripapillary choroidal changes similar to those initially seen in the right eye (Fig. 1C). At present, the bilateral intraocular inflammation remains well controlled with oral cyclosporine A (2.5 mg/kg/day) and low doses of oral prednisone (0.1 mg/kg/day). Her visual acuity is 20/100 and 20/25 in the right and left eyes, respectively. B-scan ultrasonography showed well delimited highly echogenic peripapillary choroidal lesions in both eyes (Fig. 2). Choroidal calcification was also confirmed by bilateral orbital CT scan (Fig. 2). Three-dimensional optical coherence tomography (3DOCT-1000 TOPCON, Japan) showed thickened areas at the level of the retinal pigment epithelium (RPE) and choriocapillaris presenting increased reflectivity overlying decalcified regions (white portion, Figs. 3A, 3B) with a marked irregularity of the tumor surface (Fig. 3C) and slightly thickened retina (Fig. 3E). Otherwise, the calcified regions (orange portion; Figs. 3A and 3B) showed a smooth surface of the tumor mass (Fig. 3D), intact neurosensorial retinal layers, and increased or normal reflectivity of the RPE and choriocapillaries overlying the tumor surface (Fig. 3F). Three bi-dimensional OCT sequential section images of two different capitations were measured with caliber OCT resource. Four or five measures of neurosensorial retina and RPE/choriocapillaris complex thickness were carried out on each normal, decalcified and calcified region.

Figure 1. Onset and Evolution of Choroidal Lesions. (A) Retinography of the Right Eye (RE) with Swelling and Loss of Original Contour of Optic Disk (arrow) Suggesting Optic Neuritis and Choroidal Infiltrates. (B) Optic Neuritis (arrow) Associated with Circumscribed Peripapillary Choroidal Infiltration and Macular Involvement (fine Arrow) in the RE Were Observed 2 Years After the Onset of Behçet’s Disease. (C) the Left Eye (LE) Presented Optic Neuritis (arrow) and Peripapillary Area with Choroidal Infiltration 3 Years After the Diagnosis of Behçet’s Disease.

Figure 2. B-Scan Ultrasonography Showed Highly Reflective Acoustic Plaques of Juxtapapillary Choroidal Calcification in Both Eyes (arrows). Orbital CT Axial Scan Presented Small Dense Juxtapapillary Lesions (circles) in Both Eyes, More Evident in the RE.

Figure 3. Fundus Retinography (A and B) Showed Calcified (Orange Regions; Asterisk) and Decalcified (White Regions; Circle) Areas in the Posterior Pole Surrounding the Optic Disk. Three-Dimensional OCT (C and D) Revealed Major Structural Changes at the Level of the Posterior Pole. The Surface of the Tumor was More Irregular in Decalcified (C; Asterisk) than Calcified (D) Areas. In the bi-Dimensional OCT Analysis (E and F) We Observed Increased Reflectivity (E; Large Arrow) at the Level of RPE and Choriocapillaris (130.0 ± 18.3 μm) Associated with Slightly Thickened Neurosensorial Retina (247.0 ± 17.6 μm) (E; Short Arrow) in the Decalcified Tissue (asterisk). Calcified Regions Exhibited Areas of Normal or Increased Reflectivity (F; Arrow) of RPE and Choriocapillaris (34.1 ± 5.8 μm) with Thinned Neurosensorial Retina (136.2 ± 5.8 μm). Normal RPE and Choriocapillaris (37.8 ± 4.8 μm) Complex and Neurosensorial Retina (189.6 ± 11.3 μm) were also Measured.OCT Images were Performed with a Scan Length of 6.0 × 6.0 mm into 1:2 Scales.

Discussion

Choroidal osteoma is a benign idiopathic intraocular tumor characterized by full-thickness calcification of peripapillary choroid. It can be bilateral in about 25% of cases and has a female predilection.¹ Although intraocular inflammation was apparently the precursor of the development of the choroidal lesion in the case presented herein, only a few cases of chroroidal osteoma associated with intraocular inflammation have been reported elsewhere.^3,4 Katz and Gass,³ described a patient in whom choroidal calcification was detected by CT scan far from the optic disk. Trimble and Schatz,⁴ reported a case of peripapillary choroidal calcification which appeared some years after the onset of inflammation. To our knowledge, this is the first report of choroidal osteoma associated with optic neuritis due to Behçet’s disease.

Behçet’s disease is a multifaceted syndrome characterized by oral and genital ulcers and ocular abnormalities. Although the presence of small patches of retinal whitening and retinal vasculitis are the most frequent characteristic findings in this illness, transient optic neuritis with severe visual loss is not uncommon and can be the first ophthalmologic manifestation of the disease.⁶ In these cases, it is important to rule out multiple sclerosis because the neurological features may be similar in both.

In choroidal osteoma, bi-dimensional OCT was useful to study the calcified and decalcified areas of the tumor. According to anterior analysis, areas of decalcification were associated with disruption and atrophy of photoreceptors layer in neurosensorial retina and could be considered as a risk factor for poor final vision.⁷ The bi-dimensional OCT features encountered in our patient were similar to those reported by Shields and colleagues⁸ in a previous series of 22 cases.

In conclusion, some remarkable evidences were found in the present case: an asymmetric and bilateral pattern of the choroidal lesions, the onset related to optic disk inflammation, the rapid detection of the peripapillary choroidal calcification by B-scan ultrasonography and CT scan, and the first association with Behçet’s disease. Finally, OCT can provide additional data to study posterior pole involvement in cases of calcification.^7–9 In the present case, OCT allowed dynamic examination of the posterior pole through a “scanning” exploration, which achieved a comprehensive review of the entire affected area. Secondarily, this procedure provided serial details of the depth of the damaged tissues and extracts committed with optimal correlation between the structure involved and fundus retinography location.