Dome-shaped macula simulating choroidal hemangioma in a myopic patient.

To describe a case of dome-shaped macula simulating a choroidal hemangioma and discuss multimodal imaging features to distinguish between these disorders. A 52-year-old myopic male with a refraction of -8.00 D in both eyes developed blurred vision in the left eye OS) over 4 years. Fundus examination of the right eye (OD) was unremarkable. In OS, there was a subtle orange-colored mass in the macular region with subretinal fluid, suggestive of choroidal hemangioma. Upon referral, our examination disclosed an echodense mass on ultrasonography of OS, measuring 1.0 mm thickness, and additional staphyloma was noted. Enhanced depth imaging optical coherence tomography (EDI-OCT) confirmed subfoveal fluid over a dome-shaped mass that originated in the sclera and not the choroid, consistent with the dome-shaped macula. The OD showed similar features, but to a lesser degree. Both eyes demonstrated choroidal thinning on EDI-OCT, related to high myopia. Dome-shaped macula can masquerade as choroidal hemangioma, especially when associated with subretinal fluid. In these cases, EDI-OCT can document "tumor" origin from within the sclera and not the choroid.

Introduction

Dome-shaped macula is a convex protrusion within the sclera, often found in posterior staphyloma in a myopic eye. This condition can be associated with decreased vision or metamorphopsia.[12] Traditional imaging modalities such as fundus photography, ultrasonography, and time-domain optical coherence tomography (TD_OCT) show this condition as a mass, suggestive of an intraocular tumor, including melanoma and hemangioma. Herein, we report a case referred for management of presumed choroidal hemangioma that was found on examination and enhanced depth imaging (EDI)-OCT (EDI-OCT) to represent dome-shaped macula.

Case Report

A 52-year-old myopic male with a refraction of –8.00 D in both eyes (OU) noted blurred vision in his left eye (OS) for 4 years. He was previously treated elsewhere with serial intravitreal bevacizumab (anti-vascular endothelial growth factor [VEGF]) injections for subfoveal fluid from suspected choroidal hemangioma without clinical improvement. On our examination, best-corrected visual acuities were 20/20 in the right eye (OD) and 20/70 OS. Intraocular pressure and anterior segment examination were unremarkable OU. Fundus examination of each eye revealed myopic features of optic disc tilting and tessellated choroid. However, the left eye showed additional findings of a geographic area of retinal pigment epithelial (RPE) atrophy in the macula with subtle elevation [Figure 1].

Figure 1

A 52-year-old male with high myopia referred for circumscribed choroidal hemangioma but found to have dome-shaped macula. (a-b). Fundus photos of right (a) and left (b) eyes show tessellated fundus. In addition, mild retinal pigment epithelial (RPE) atrophy of the macula was seen in the left eye (b) without a distinct mass clinically. (c-f). Fluorescein angiography was normal in right eye (c) but showed window defect corresponding to RPE atrophy in the left eye (d), while indocyanine green angiography was normal in both eyes (e-f)

Ultrasonography disclosed an echodense, smooth, dome-shaped mass in the macular region within a posterior staphyloma that appeared hypoautofluorescent on autofluorescence imaging. Fluorescein angiography showed window defect corresponding to the RPE atrophy OS and normal findings OD while indocyanine green angiography was unremarkable OU. EDI-OCT of each eye showed a smooth dome-shaped elevation of the submacular sclera of 1.0 mm thickness that was more pronounced and associated with subfoveal fluid OS, as well as diffuse choroidal thinning OU [Figure 2]. These features were consistent with dome-shaped macula associated with myopia. Treatment options for the subretinal fluid included photodynamic therapy, anti-VEGF injections or laser photocoagulation. The patient elected to have continued intravitreal bevacizumab injections on a monthly basis.

Figure 2

Ultrasonography (US) and optical coherence tomography (OCT) findings in dome-shaped macula simulating choroidal hemangioma. (a and b) B-scan US showed long axial lengths in both right (a) and left (b) eyes. There was a dome-shaped elevation of the posterior pole in the left eye (b). There was no subretinal fluid in either eye on US. (c and d) Enhanced depth spectral domain OCT demonstrated choroidal thinning and scleral thickening in macula, causing a smooth dome-shaped elevation that was less prominent in right (c) than left (d) eye. (d) Subfoveal fluid was also noted in left eye

Discussion

Dome-shaped macula can be seen in 10% of myopic patients with refraction greater than –8.00 D and is often bilateral but can be asymmetric as in our case.[1] Subretinal fluid is present in 50% of patients and is characteristically located at the peak of the dome.[1] This appearance is related to compensatory scleral thickening within a staphyloma, believed to be an adaptive response of axial myopia.[23456] Imamura and colleagues hypothesized that the scleral thickening led to obstruction of uveoscleral outflow and hence accumulation of subretinal fluid in these eyes.[2]

Our patient was previously diagnosed with circumscribed choroidal hemangioma and subretinal fluid. Clinically, choroidal hemangioma has a red-orange color, appears as a smooth, dense mass on ultrasonography, and can manifest occasional subretinal fluid, similar to the dome-shaped macula. Fluorescein angiography of hemangioma shows diffuse hyperfluorescence with leakage whereas dome-shaped macula would remain without fluorescence or with occasional staining from subretinal fluid. Indocyanine green angiography of hemangioma shows bright hyperfluorescence with a characteristic “washout” phenomenon, unlike the isofluorescence of the dome-shaped macula.[78] TD-OCT shows both hemangioma and dome-shaped macula with smooth, dome-shaped elevation and related subretinal fluid.[7] Unfortunately, TD-OCT cannot differentiate between these two conditions.

The best way to differentiate choroidal hemangioma from dome-shaped macula is with spectral domain EDI-OCT. This technique allows visualization of the choroid and sclera with cross-sectional imaging.[9] EDI-OCT has been used extensively in ocular oncology to visualize retinal, choroidal, and scleral tumors.[10] On EDI-OCT, circumscribed choroidal hemangioma appears as a hyperreflective choroidal mass with the expansion of choroidal vessels, whereas nevus shows compression of the overlying choriocapillaries.[10] In both cases, the scleral thickness is normal.[10] On the other hand, dome-shaped macula shows scleral, not choroidal, thickening with overlying choroidal thinning from related myopia. These features serve to differentiate dome-shape macula from choroidal tumors.[210]

In summary, we present a case of dome-shaped macula initially suspected elsewhere to be a choroidal hemangioma with leakage, but subsequently, we identified EDI-OCT features of the dome-shaped macula. Spectral domain EDI-OCT plays an important role in the differentiation of intraocular tumors and simulating lesions.[10]