D31.31-32 Benign Neoplasm of Choroid

Choroidal nevus is a benign tumor caused by proliferation of the melanocytes normally found in the uvea.  

The lesion is characterized by the following clinical features:

• Usually no change in visual acuity
• Clearly defined margins
• Flat or slightly elevated
• Stable in size over time
• Overlying drusen
• Retinal pigment epithelial atrophy
• Hyperplasia
• Fibrous metaplasia
• Subretinal fluid
• Orange pigment

Structural Damge to the Eye

• None
• Subretinal and/or intraretinal fluid 
• Cystoid retinal edema
• Choroidal neovascularization

Functional Damage to the Eye

• None
• Central and peripheral vision loss secondary to retinal complications

The main goal of the diagnostic evaluation in a patient with choroidal nevus is to accomplish the following:

• Evaluate tumor location, color, size and thickness
• Determine visual acuity
• Obtain baseline fundus photographs
• Rule out malignant choroidal melanoma

Patient History

The symptoms of choroidal nevus vary from no symptoms to severe visual impairment.  Patients with a large nevus may have mild visual impairment secondary to retinal complications.

Patients with a choroidal nevus may present with any of the following abnormal clinical signs or symptoms:

• None
• Central and peripheral vision loss secondary to subretinal fluid

Clinical Appearance of the Retina

DIAGNOSTIC TESTS

Fundus Photography

• Document the size, shape, color, location and height of choroidal nevus
• Document associated clinical features of choroidal nevus

Retinal Laser Scan

• Document the presence or absence of subretinal fluid at the macula

B-Scan Ophthalmic Ultrasound

• Document the presence or absence of ultrasound hollowness within the choroidal nevus
• Document the height of the choroidal nevus
• Document the presence or absence of choroidal tissue excavation
• Follow-up for at least 1.5 years may be necessary to differentiate between a choroidal nevus and a choroidal melanoma

A choroidal nevus may be pigmented or non-pigmented. 

Choroidal Melanoma

Risk factors for identification of a small choroidal melanoma (when it might resemble a nevus), have been identified. Documented growth/change of a choroidal nevus over one to two years is a characteristic of malignant transformation.

Risk Factors that are Predictive of Tumor Growth Thickness greater than 2 mm Subretinal fluid Symptoms of reduced vision or photopsia Orange pigment Tumor margin less than or equal to 3 mm from the optic disc Ultrasound hollowness Absence of surrounding depigmented halo Absence of overlying druse

The treatment of a benign choroidal nevus is determined by its risk of malignant transformation into a choroidal melanoma.

• Patients with no suspicious features require no treatment
• After the initial diagnosis, patients should be monitored twice during the first year
• Subsequently, annual surveillance examinations are recommended as long as the nevus remains stable

It is not common for a choroidal nevus to transform into a malignant melanoma.  The annual rate of malignant transformation is estimated to be 1 in 8,845.  The rate of malignant transformation increases with age and by age 80 the rate increases to 0.78%.

• A choroidal nevus that has one risk factor for growth has a 3% chance of growth at five years
• Patients with one or two risk factors should be examined every six months
• A choroidal nevus with three or more risk factors has a 50% chance of growth at five years and probably represents a small choroidal melanoma

1.  Cheung A, Scott I, Murray T, Shields C.  Distinguishing a Choroidal Nevus From a Coroidal Melanoma.  American Academy of Ophthalmology.  http://www.aao.org/publications/eyenet/201202/pearls.cfm.  Last accessed June 6, 2014.
2.  Zolotarev F, Turaka K, Shields C.  SMall Choroidal Melanoma With All Eight Risk Factors for Growth.  http://bmctoday.net/retinatoday/pdfs/1010RT_Oncology_Zolotarev.pdf.  Last accessed June 6, 2014.
3.  Reed K.  Is It A Nevus Or Melanoma?  Optometric Management. 2011 Sept. 1.http://www.optometricmanagement.com/articleviewer.aspx?articleID=106126.  Last accessed June 7, 2014.