Diagnosis and Discussion
Diagnosis
Metastatic melanoma to the liver from a primary choroidal melanoma.
Discussion​
Choroidal melanoma is a type of uveal melanoma, which comprises 3-5 percent of melanomas and is the most frequently occurring adult intraocular malignancy. The uvea consists of the iris, the ciliary body and the choroid. The choroid is found between the sclera and the retina and is a pigmented and vascular layer which provides support to the retina. The vast majority (over 90 percent) of uveal melanomas arise from the choroid, with the ciliary body and iris less commonly affected. Uveal melanoma has a propensity to metastasize, with 50 percent of patients experiencing metastasis within 10 years of diagnosis. The most frequent site of metastasis is the liver, seen in 89 percent of metastases. Other sites of metastasis include the lungs and bone. Uveal melanoma has a high mortality due to the frequency of metastasis, with a median survival of 6-12 months after metastasis has occurred.
The prognosis of uveal melanoma is influenced by a variety of factors. Tumor basal diameter and depth, mitotic count and chromosomal abnormalities (such as monosomy 3, loss of 1p, 8p and 6q and gain of 8q) are a few of the tumor characteristics that influence prognosis. Treatment of uveal melanoma includes eye-sparing techniques, such as local surgical resection, laser therapy and radiation, often with plaque brachytherapy. In some cases, such as those with extraocular spread or large tumor size, enucleation may be performed. Even when local control of disease is obtained metastasis remains a concern and can occur years after initial treatment. As in our patient, surveillance is recommended to monitor for metastasis, as the prognosis is quite poor once this occurs.
References
Kaliki S, Shields CL, Shields JA. Uveal melanoma: estimating prognosis. Indian J Ophthalmol. 2015;63(2):93–102. doi:10.4103/0301-4738.154367
Rashid AB, Grossniklaus HE. Clinical, pathologic, and imaging features and biological markers of uveal melanoma. In: Thurin M, Marincola FM, editors. Molecular diagnostics for melanoma: Methods and protocols Totowa, NJ: Humana Press; 2014. p. 397-425.
Yang J, Manson DK, Marr BP, Carvajal RD. Treatment of uveal melanoma: where are we now? Ther Adv Med Oncol. 2018;10:1758834018757175. Published 2018 Feb 21. doi:10.1177/1758834018757175