Increasing Vision Difficulty

Patient presented with vision difficulty for one year, which increased in severity over last two months.

Figure 1. On ultrasound, an elevated, dome shaped echogenic lesion is noted in posterior wall just superior to optic nerve head. On color Doppler study, the lesion shows internal vascularity with arterial spectral wave form.

Figure 2. MRI plain imaging axial, sagittal and coronal image shows altered signal intensity (hypo intense on T2WI and iso to hyper intense on T1WI) lesion is noted in posterosuperior segment of left eye in close relation with optic disc.

Figure 3. MRI contrast imaging axial, sagittal and coronal image shows lenticular shaped homogeneously enhancing altered intensity lesion in posterosuperior segment of left eye in close relation with optic nerve.

Ophthalmoscopy showed a large melanotic mass filling the left posterior segment.

An elevated, dome-shaped echogenic lesion of 8 mm × 4 mm is noted in posterior wall just superior to optic nerve head

A well-defined lenticular shaped homogeneously enhancing altered intensity lesion in posterosuperior segment of left eye in close relation with optic nerve associated with choroidal effusion.

With an incidence of six per million per year, ocular melanomas are the most common primary intraocular malignancy in adults.

Ocular melanoma is not considered an inherited disease, although recent studies suggest a genetic component.

Melanomas are malignant neoplasms of melanocytes.

Melanomas are divided into amelanotic or melanotic types by macroscopic visualization of pigmentation.

There are two basic melanoma cell types: spindle and epithelioid.

Ocular melanoma is often associated with exudative retinal detachment extending from the tumor margins and over the apex.

Presenting signs and symptoms of ocular melanoma include decreased visual acuity, field defects, blurred vision, floaters, photopsia, and ocular pain.

A-mode characteristics include a fixed solid mass, low to medium reflectivity, and regular vascularity (seen dynamically as spontaneous rapid spike movements).

B-mode findings include characteristic mushroom or collar-button shape and choroidal excavation (loss of normally highly reflective choroid echoes).

Early MR studies reported that melanomas demonstrated marked T1 shortening compared with other malignant tumors.

However, grossly amelanotic tumors also may produce T1 shortening, perhaps because of microscopic amounts of melanin.

MR can be helpful in differentiating between melanoma and subretinal fluid.

Early studies reported clinical misdiagnosis rates as high as 40%.

Extrascleral local extension occurs via scleral emissary channels for neurovascular structures and is associated with increased risk of recurrence and hematogenous dissemination.

Treatment is largely determined by tumor size.