A choroidol melanoma is a malignant tumour composed of melanocytes pigment containing and producing cells, normally present in the choroid. It is the most common intraocular malignancy in adults. The incidence of melanoma is highest from ages 50-70 and is same in men and women. Very few cases occur in people under 30 years of age. The cause of choroidal melanoma is unknown. Inheritance seems to be of little importance. There is some evidence that environmental factors (carcinogens such as cigarette smoke) may play a role. Choroidal melanomas may produce no symptoms initially if located away from macula.

A tumour that develop next to or in the macula may produce distorted or reduced vision. Tumours located away from the macula may produce changes in the visual field and patient may develop changes in the vitreous and produce flashes of light or floaters. Retinal detachment, glaucoma and rarely pigmentation of sclera are some of the manifestations of the choroidal melanoma.

A 70 years male patient came in the out patient department of ophthalmology in Nair hospital with gradual loss of vision and axial proptosis of right eye over a period of 6 months (Fig. 1). Patient had history of cigarette smoking for 50 years. On examination the vision in right eye was found with no perception of light in all the quadrants. Extraocular movements of right eye were absent. Right eye upper lid was oedematous and distorted with bulbar conjunctiva showing chemosis . Cornea of right eye showed features of exposure keratitis. Exophthalmometry with Hertels exophthalmometry showed axial proptosis of 36 mm and left eye 20 mm from lateral orbital margin. The right eye showed black mass involving entire eye behind the equator. On direct and indirect ophthalmoscopy the posterior segment details were not visible. The examination of left eye revealed that it was absolutely normal.

On USG-B-scan of right eye showed a dome shaped mass involving uveal tract and the entire posterior segment along with the optic nerve infiltration. The mass had reflectivity and cascading effect and measured about 10.6 X 8.6 mm in size. It also showed inferior exudative retinal detachment of right eye.

Fig. 1 : Axial proptosis Rt eye.

On CT scan with orbital and brain cuts of right eye showed dome shaped mass involving entire eye upto equator, erosions of medial wall and floor of the orbit (Fig. 2).

The lateral wall of right eye showed black pigmentation. Infiltration of the extraocular muscle was also evident. Infiltration of the optic nerve except posterior part of optic nerve near the canal was evident.

Blood investigations, USG abdomen, X-ray chest PA view were normal. The Exenterated mass measured about 8 mm X 10 mm (Fig. 3).

The exenterated mass was sent for histological examination which showed large oval round epithelial cells with well-demarcated cell membranes, eosinophilic cytoplasm and round nuclei with prominent nucleoli. The patient was followed up for about 8 months after surgery and was found to have no metastatic involvement of other organs. Patient later didn’t followed up. The relative of the patient reported after about one year that the patient died due to Juandice in village.

Choroidol melanoma constitutes 80% of all the intraocular tumours. The incidence is highest in the age group of 50-70 age. The sex ratio is equal for both men and women. Very few cases are recorded below 30 years of age. The cause of choroidal melanoma is unknown. Inheritance seems to be of very little importance. Environmental factors such as cigarette smoke may play a role by influencing benign pigmented cells to change into malignant cells. The white population are more affected than black. Choroidal melanomas are very uncommon in Indian population. Diagnosis can be made clinically, aided by radiological and blood investigations. The blood investigation included liver function test which can reveal metastatic changes in liver. In radiological methods. B-scan, aided with A-mode can reveal the size, shape excavation and shadowing in the orbit. CT-scan and MRI are used to rule out extraocular metastasis.

Fig. 3 : The operated mass measured 8 mm x 10 mm.

Fluorescence angiography is used to detect extensive leakage with progressive fluorescence, late staining of the lesion. X-ray chest and mammography are also used to detect metastasis. Indocyanine green angiography, colour-coded doppler and fine needle aspiration biopsy are also used in diagnosis. Positron emission tomography, 31P magnetic resonance spectroscopy and monoclonal antibody tagged with a short lived radioactive technetium 99m tracer are new modalities of investigation. Mortality of the patients depends upon the types of cells the tumour has.

Tumours less than 10 mm in elevation and less than 20 mm in basal diameters are treated with plaque radiotherapy. The procedure involves outlining the tumour with methylene blue which is further outlined with diathermy. A transparent perspex dummy applicator is temporarily centred over the tumour and pre-placed sutures are inserted.

The dummy applicator is replaced with a radioactive plaque of same size. 25I is considered ideal for intraocular tumours. With energy of 0.039 Mev and it lacks alpha or beta rays.12 Other isotopes used are radon with energy range of 0.22 to 2.20 Mev and short life of 3.8 days. And 60Co with energy of 1.77 to 1.33 Mev.6 The disadvantage of these isotopes is high tissue penetration which may cause damage to normal tissue. The response of the therapy can best evaluated by clinical examination, colour photograph and utlrasonography of the tumour. Tumour regression starts after 1-2 months of the treatment.