Moles or nevus in the back of the eye. Should we be worried?

07/05/2024

Nevi, also commonly known as moles or freckles, are more or less pigmented lesions that can appear in various parts of the body, especially on the skin and also, although less frequently, in the back of the eye (in a tissue called posterior uvea or choroid). Although in most cases choroidal nevi do not represent a serious health problem, it is important to know that they require highly specialized medical attention.

Unlike cutaneous moles, choroidal nevi are not related to sun exposure. These lesions are largely congenital and are usually present from birth or develop during childhood. Although most nevi are benign, they have a tendency to grow (especially in young patients) and, occasionally, some can degenerate into a malignant lesion.

Periodic monitoring of a nevus is essential. The ophthalmologist must perform a thorough examination to rule out clinical signs that could carry a greater potential risk of conversion to a malignant lesion. In some cases, additional imaging tests, such as autofluorescence retinography, ocular ultrasound, and optical coherence tomography, are necessary to obtain more precise data on the lesion. Among the most relevant clinical signs that the doctor must analyze, the size of the nevus (both in extent and height), its documented growth, the presence of fluid or associated pigment and the behavior of the lesion in the ultrasound study stand out. Depending on the findings of the clinical examination, the specialist ophthalmologist will decide the frequency with which the patient should perform the checks.

According to studies published in the international literature, only 0.0005% of nevi can become melanoma. When a choroidal nevus already shows several signs of transformation into melanoma, it is advisable to perform an extension study to assess whether there is dispersion of cells to other organs. In these cases, it is essential to have a multidisciplinary medical team. Cases with a diagnosis compatible with melanoma, even of small size, must be treated with highly specialized conservative methods (laser, local radiotherapy -brachytherapy- or surgical resection) or with enucleation of the eyeball in the event that the tumour is large or does not respond to other alternatives.

Dr. Javier Elizalde, ophthalmologist at the Barraquer Ophthalmology Centre