How Common Is Ocular Melanoma Or Is It A Rare Disease?

Ocular melanoma is a cancerous disease of the eye that usually appears in adults of old age. The cancerous growth is seen in the pigment-producing cells of the middle layer of the eye, which is res color to the eyes. It is usually primary cancer that has originated from the eye only. However, it is a very rare cancer that affects people worldwide. It is represented by symptoms like bulging growth in the pupils, blurred vision, loss of peripheral vision, etc.

Ocular melanoma (OM) is an extremely rare type of cancer that develops the eye. It presents an incidence of 5 per million adults in the world. Although it is rare, it is still the most common primary cancer that originates from the eye in adults. Primary cancer is that cancer began at that site and has not spread in that site from other parts of the body.⁽²⁾

Although skin melanoma has increased in frequency over the last several decades, while ocular melanoma has not shown such elevation. Nearly six people per 1 million are diagnosed with ocular melanoma in the U.S. each year, whereas invasive melanoma of the skin has affected approximately 1 in 50 Americans every year. This incidence is reported similarly in other Caucasian populations worldwide. According to an article published in Clinical Ophthalmology in the year 2017, eye melanoma accounts for about 3-5% of all melanomas.⁽¹⁾

Although ocular melanoma is the most common type of eye cancer in adults, it is not widespread. Overall, its incidence rate is about 5 to 6 people per million; in other words, it affects fewer than 3,000 people in the United States every year.⁽³⁾

In most of the cases, OM arises in the middle part of the eye known as the uveal tract. The uveal tract is the colored (pigmented part) layer of tissue that is located beneath the white of the eye (sclera). It comprises pigmented cells and blood vessels. It has three parts-

Iris- In the front of the eye, the uvea is made up of the colored part of the eye, which is known as iris.

Ciliary Body- Ciliary body is a circle of muscle tissue that releases a transparent fluid (aqueous humor) into the eye and helps to maintain the shape of the lens.

Choroid- It is the largest area of the uveal tract that lies in the back part of the eye. It is located beneath the retina (the vision sensing area of the eye).⁽²⁾

In most cases, it is reported that ocular melanomas develop within the choroid. Ocular melanoma occurs in the pigment-producing cells of the eye called melanocytes. It is a cancerous (malignant) tumor that has the potential to spread (metastasize) to other parts of the body. It mostly metastases to the liver. The exact cause of this disorder is not clear, but several risk factors are identified.⁽²⁾

Melanocytes found in the choroid have similar functions as compared to those cells found in the skin. Both of them produce skin pigment. When choroidal melanocytes divide and form cancerous cells, then it is called choroidal (or uveal) melanoma. However, skin melanoma and uveal (ocular) melanoma are biologically and genetically different in disease manifestations and characteristics, but they share similar names. It is an extremely rare condition that skin melanoma can spread into the eye and also unusual for ocular melanoma to spread to the skin.⁽²⁾

Conclusion

Ocular melanoma is not common cancer. It develops in the eyes of the primary tumor. It rarely develops as a result of other cancers developed in other parts of the body. It shares similar names with skin cancer but has different symptoms and characteristic features.

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How Common Is Ocular Melanoma Or Is It A Rare Disease?