Ciliary body melanoma
Encyclopedia
Ciliary Body Melanoma is a type of cancer
arising from the coloured part (uvea
) of the eye
.
About 12% of uveal melanoma
arise from the ciliary body.
The tumour is usually diagnosed by clinical examination with a slit-lamp utilising a triple mirror contact lens. Ultrasonography and fine needle aspiration biopsy (FNAB) are also sometimes helpful in confirming the diagnosis.
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
arising from the coloured part (uvea
Uvea
The uvea , also called the uveal layer, uveal coat, uveal tract, or vascular tunic, is the pigmented middle of the three concentric layers that make up an eye. The name is possibly a reference to its reddish-blue or almost black colour, wrinkled appearance and grape-like size and shape when...
) of the eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
.
About 12% of uveal melanoma
Uveal melanoma
Uveal melanoma is a cancer of the eye involving the iris, ciliary body, or choroid . Tumors arise from the pigment cells that reside within the uvea giving color to the eye...
arise from the ciliary body.
Clinical features
It occurs most commonly in the sixth decade.- External signs include dilated episcleral blood vessels (sentinel vessels). Extraocular erosion may produce a dark mass beneath the conjunctivaConjunctivaThe conjunctiva covers the sclera and lines the inside of the eyelids. It is composed of rare stratified columnar epithelium.-Function:...
. - Pressure on the lensLens (anatomy)The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. The lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a...
by the enlarging tumor can cause astigmatismAstigmatismAn optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances...
, sublaxtion of the lens and formation of a localised lens opacityOpacity (optics)Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc...
. - The tumor can erode forward through the iris root and mimic an iris melanomaMelanomaMelanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...
. - Retinal detachmentRetinal detachmentRetinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. It is a medical emergency.The retina is a...
can be rarely caused by posterior extension of the tumor. - Anterior uveitisUveitisUveitis specifically refers to inflammation of the middle layer of the eye, termed the "uvea" but in common usage may refer to any inflammatory process involving the interior of the eye....
is an uncommon presentation and occurs due to tumor necrosisNecrosisNecrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
. - Cirumferentially growing tumors carry a bad prognosisPrognosisPrognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
as they are diagnosed late. - At times the tumor is detected as an incidental finding during routine examination.
The tumour is usually diagnosed by clinical examination with a slit-lamp utilising a triple mirror contact lens. Ultrasonography and fine needle aspiration biopsy (FNAB) are also sometimes helpful in confirming the diagnosis.