Case Study 1: Choroidal osteoma

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Abstract

A 33 years old female presented to us as a case of choroidal osteoma.The tumor was unilateral and in a juxtapapillary site. The tumor was slightly elevated from the retinal plane.Visual acuity was markedly affected. Bscan, fluoroangiography and OCT was performed.

Choroidal osteoma or osseous choristoma is a rare, benign bony tumor that typically arise from the juxtapapillary choroid and are seen in adolescent to young adult (ie; second to third decade) patients, more commonly in females. It is usually unilateral but may be bilateral in 20-25% cases. The characteristic lesion appears yellow to orange and has well-defined, scalloped margins. Histologically, the tumor is composed of compact bone located in the peripapillary choroid. Choroidal osteomas typically enlarge slowly over many years. If these lesions involve the macula, vision is generally impaired. The etiology of these lesions is unknown.

Figure I  Right eye. A solid mass located in the juxtapapillary region. The mass had a yellowish white centre and was elevated from the retinal plane Left eye. Revealed normal appearance

Case report

A 33 years old lady presented with the complaints of dimness of vision for last 1 year. Before that,she had no relevant medical history.On examination,her BCVA in right eye was CF-5ft.In the left eye visual acuity was normal. Anterior segment was normal.Fundus examination revealed a well defined yellow orange lesion of about 4×3 papillary diameters locate din the juxtapapillary region. The mass was elevated from the retinal plane and had a yellowish white centre (Fig 1).

Echography showed the lesion as a solid, raised subretinal mass with an extremely high reflectivity (Fig 2). The echographic images of the lesion showed extremely high reflectivity from the retinal surface with shadowing corresponding to the tumour site. In the remaining areas the thickness of the retina and choroid was normal; the optic nerve was also of normal diameter and reflectivity.

Fig 2:high reflectivity even in lower gain in left sided image. Shadowing due to the lesion in right sided image. 

Fluorescein angiography showed a pattern of irregular hyperfluorescence overlying the tumour. Numerous capillaries on the surface ofthe choroidal osteoma were present in the early phase of the angiogram (Fig 3).

Fig 3: FFA shows mottled hyperfluorescence

Fig 4: OCT of right eye shows elevated chorio-retinal complex with hyperreflectivity.

In summary, choroidal osteoma is a rare and benign choroidal tumor of healthy eyes of healthy young women wherein normal choroid is replaced with mature bone. It is primarily a clinical diagnosis,presenting as yellow juxtapapillary subretinal patches with scalloped borders. B-scan assists the diagnosis with densely hyperechoic concave band at the level of the choroid and optic nerve, which persists on decreased gain. Our patient is now in our observation.