DX: Choroidal Melanoma

Here is the conlusion of the case. It was obvious the asymmetry of orbits corresponding to changes in posterior chamber of right eye.

It was hyperintense in T1/ hypo in T2, so hemorraghic changes are considered. It had no classical signs of retinal or choroidal detachment, instead there was an intraocular globular amorphus mass. Post gad images revealed mass enhancement and no peripheral involvement.

Here's a descriptive T2 snd T1 slice:

Red arrow shows the posterior chamber involvement and on the right it shows the globular appeareance of the mass.  Blue arrow shows an incidental sellar arachnoidocele.

Here is the "mushroom like" appeareance of Choroidal Melanoma. Photo Courtesy of AFIP Atlas of Tumor Pathology.

Choroidal melanoma is the most common primary malignant intraocular tumor and the second most common type of primary malignant melanoma in the body. It is nevertheless an infrequently found tumor.

Is a subtype of uveal melanoma. Uveal melanomas can be divided into 2 categories: (1) anterior uveal melanomas, in which the tumor arises in the iris, and (2) posterior uveal melanomas, in which the tumor arises in either the choroid or the ciliary body. Intraocular melanomas simultaneously can involve more than 1 uveal structure.

The ocular tissue where these tumors arise, the uvea, is a densely pigmented layer that forms part of the wall of the eye. The uvea is subdivided into the iris, the ciliary body, and the choroid. The choroid underlies the retina and its pigment epithelium throughout the ocular fundus. The main function of the uvea is to provide oxygen and other nourishment to the highly metabolically demanding retinal photoreceptors. It is primarily a vascular tissue, with fenestrated capillaries and stroma containing melanocytes.

Incidence of primary choroidal melanoma is about 6 cases per 1 million population. Perhaps because of increased sunlight exposure, there appears to be a higher incidence of uveal melanoma in the southern latitudes of the United States. Alternatively, this might be the effect of a tendency of older Americans to retire in the South.

Choroidal melanomas remain asymptomatic for prolonged periods of time; they may be found incidentally during ophthalmoscopy. In general, the more anterior their origin, the longer the delay of any symptoms.


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