User:Dabajeh27/sandbox
Conjuctival Nevus[edit]
Conjuctival nevus is derived from conjunctiva- a noun meaning the mucous membrane that lines the inner surface of the eyelids and is continued over the forepart of the eyeball[1] and nevus- singular, nevi (plural), a congenital pigmented area on the skin: Birthmark[1]. Conjuctival nevus can turn into a melanoma, a malignant (cancerous) tumor, containing dark pigment, of the conjunctiva.
Structure[edit]
In order to understand the condition conjunctival nevus one should understand the basic structure of the eye. The eye is composed of many particular accessory organs, nerves, muscles and blood vessels. The eye is a hollow spherical structure that is separated by three layers. The outer layer or white part of the eye is called the Sclera. In the middle layer is the Choroid coat, which contains blood vessels that nourish surrounding tissues. Also, is the inner Retina layer that houses nerves. The front transparent portion of the eye bulges out and forms the Cornea, which is used for light transmission and refraction. The Retina is continuous with the optic nerve in the back of the eye. The Retina contains photoreceptor cells (visual receptor cells).[2]</sup
The conjunctival nevus is one of the most common benign tumors of the ocular surface. Conjunctival Melanomas are rare; they can arise without a preexisting conjunctival nevus, or due to malignant transformation in case of PAM (primary acquired melanosis). A retrospective study analyzed 70 patients with pigmented lesion of the conjunctiva in period 1996-2006 at the Department of Ophthalmology, Faculty of Medicine, Comenius University, Bratislava, with the aim to determine the frequency of change in size and pigmentation of these benign (non-cancerous) lesions. Epibulbar pigmented lesions are rare, recognition of their precursor's lesions at an early stage is important. Surgical excision is usually effective in eradicating these lesions. Extensive cases of flat PAM (primary acquired melanosis) with atypia may be managed with mitomycin C. Multifocal. Advanced conjunctival melanoma, especially showing intraocular or orbital invasion, may require exenteration (removal of the eye/components) and/or radiotherapy to adequately extirpate (to destroy completely) the neoplasm (tumor) locally. However, systemic metastases might have already developed in patients with advanced stage of disease.[3]
Signs and Symptoms[edit]
Melanomas can develop in the lining of the eyelid (conjunctiva) or the thin pigmented coating within the eyeball (choroids). Signs and symptoms include: a feeling of “scratchiness” under the eyelid, and a dark spot on the eyeball. Melanomas on the surface of the eye may be spotted during an eye examination. Early diagnosis and treatment are essential to stop the potential of cancer spreading. Anyone with suspected ocular melanomas should see an ophthalmologist without delay. Discussion of the diagnosis and treatment for conjunctival melanoma is beyond the scope of this article.[5]
Frequently Asked Questions[edit]
Just like a raised freckle on the skin, a nevus can occur inside your eye. And, like a nevus on the skin, a choroidal nevus can grow into a melanoma. This is why your ophthalmologist will examine your eyes on a regular basis (at least every six months) and use photography and echography to check if the nevus has changed in size.
- Is conjunctival melanoma the same as skin melanoma?
Melanoma is the term used to describe a cancer that develops from cells called melanocytes. Melanocytes are the cells that produce a dark colored pigment called melanin and this pigment is responsible for the color of our skin. These cells are found in many places in our body including the skin, hair, and lining of the internal organs. Although, most melanomas develop within the tissue of the skin, it is possible for it to arise in other parts of the body, such as the eye.
- What causes conjunctival melanoma?
Unlike skin melanoma, there is no convincing evidence to show that sunlight causes choroidal melanomas. Like many other forms of cancer, the exact cause is unknown. Conjunctival melanoma is more common in people with lighter skin and in those over sixty years of age (although a significant number of patients are thirty or younger). Other predisposing factors that have been identified include exposure to ultraviolet radiation, genetics, or having a nevus (freckle). It occurs equally in men and women, and in left or right eyes. As far as we know, there is nothing you can do to prevent conjunctival melanoma.
Biopsies are performed with some types of eye cancers such as eyelid tumors but are not recommended for choroidal melanomas. Fine-needle biopsy of a suspected melanoma is rarely done because the risks far outweigh the benefits. Tumor seeding (spread of the cancer cells) has been reported with fine-needle biopsy. Experienced ocular oncologists can diagnosis ocular melanoma without a biopsy.
Studies show that the laser just burns the surface of the melanoma, which can leave cancer cells under the surface and in the wall of the eye. If the cancer is not killed or removed, there is a possibility that it will spread throughout the body.
- Can a conjunctival melanoma tumor be surgically removed without radiation therapy or removing the eye?
Surgery to remove just the tumor could allow tumor cells to float into the spaces around the eye. Furthermore, studies have shown that up to 50% of choroidal melanomas already have invaded the sclera; therefore the entire tumor would not always be removed or treated. Many eyes do not tolerate this procedure and will suffer detachments of the retina, hemorrhages, or having the eye removed anyway.
- Will the cancer spread to other parts of my body?
Only about 2% of patients are found to have the cancer spread (metastasize) at the time they are diagnosed with a choroidal melanoma. Before surgery, you may be seen by a radiation oncologist and have medical testing to see if there are any signs of cancer elsewhere in your body. Unfortunately, after treatment some people do develop metastasis. This is thought to be caused by undetectable microscopic cancer cells present at the time of treatment that cannot be detected by current testing. While your doctor may be able to give you an approximation of developing metastasis based on your tumor's size and location; no one can give you a guarantee that the cancer will not spread.
- What are the side effects of the radiation therapy?
The type of radiation used in eye-plaque therapy should not cause hair loss, nausea, brain damage, or affect the other eye. Once the radiation plaque is removed, there will be no radiation left in your body, on your clothing, or on any of your personal belongings. The effects of the radiation delivered to the tumor and eye will continue to be observed for months and years after treatment. Radiation plaque therapy may cause eventual blurring, dimming, or rarely a total loss of vision in the treated eye. Plaque radiation does not affect the vision in the other eye. The amount of vision loss depends on what your vision was before treatment, how close the tumor is to the center of your eye, and how sensitive your tissues are to radiation. Most people maintain some central vision, and almost all retain peripheral vision.
- Will a person be blind or visually impaired from eye cancer?
Most people who have an eye cancer do not become blind or significantly visually impaired.[4]
References[edit]
- A. Merriam-Webster’s Collegiate Dictionary Tenth Edition. Copyright 2001 by Merriam-Webster, Incorporated Springfield, Massachusetts, U.S.A. ISBN 0-87779-709-9
- B. Hole’s “Human Anatomy & Physiology” twelfth edition. By David Shier, Jackie Butler, and Ricki Lewis. ISBN 978-0-07-352570-9. Publisher McGraw-Hill ; Copyrighy 2010. Pages 462-470
- C. http://www.bmj.sk/2007/10807-02.pdf
- D. http://www.eyecancermd.org/faq.html
- E. http://www.skincarephysicians.com/skincancernet/hidden_melanomas.html#Eye