Although recognized as a rare condition, ocular melanoma is the most common ocular primary malignancy, representing 5% of all melanomas [1], [2]. Among ocular melanomas, nearly 85% occur in the uveal tract [1], [2], of which 85–90% arise from the choroid, followed by the ciliary body (5–8%) and the iris (3–5%) [2], [3], [4], [5], [6].

The incidence of UM in Europe has been reported as ranging from 2 cases per million per year in Southern Europe to over 8 cases per million per year in Northern countries [7]. In Asia and Africa the reports point to a significantly lower incidence rate, of less than 1 case per million per year [6], [8].

Advanced age is related to higher incidence rates, with both mean and median ages at diagnosis of approximately 62 years old [6], [9], [10], [11]. Regarding incidence by gender, there is not a true consensus, with variable results according to different studies [6].

Along with location, tumour size, extrascleral extension and associated complications will determine clinical presentation, with most patients complaining of decreased visual acuity and blurred vision; about 30% are asymptomatic at presentation [6], [12], [13], [14], [15].

Clinical characteristics as older age at presentation, male gender, larger tumour basal diameter, increased tumour thickness, ciliary body location, diffuse configuration, association with ocular/oculodermal melanocytosis, extraocular extension at presentation and advanced AJCC stage [16] have been pointed as predictive clinical features of worse clinical outcomes [17].

Currently, primary local treatment options for UM, depending on the tumour location and dimensions, include globe-sparing modalities as tumour resection and radiation therapy, which comprises plaque brachytherapy and teletherapy (specifically proton beam). In contrast, primary enucleation remains a valuable treatment option in large tumours and blind painful eyes [6]. Although satisfactory local disease control is generally achieved with these modalities, long-term survival rate for patients with UM remains poor, with approximately half resulting in clinical metastases by 10 years, with liver being the first site involved in 90% [17], [18]. For metastatic disease, the prognosis is very poor, with a median overall survival of 10–13 months [18].

A dedicated UM Oncology Unit was established in Coimbra in July 2013. Prior to this, all patients with exception of those treated by primary enucleation were referred to another European country for conservative treatment. To the best of our knowledge, there are no large studies reporting the clinical demographics and epidemiology of UM in Portugal. Therefore, the purpose of this study is to report clinical features and epidemiology of the Portuguese population with UM diagnosed and treated at the National Reference Center since its foundation until December 2022.