Amelanotic Uveal Melanomas Evaluated by Indirect Ophthalmoscopy Reveal Better Long-Term Prognosis Than Pigmented Primary Tumours-A Single Centre Experience

Simple Summary The prognosis of uveal melanoma is dependent on many factors. Among the most relevant are the tumour size, ciliary body involvement, extraocular extension, tumour cell type, genetic abnormalities, and the presence of lymphocytic infiltration. The assessment of some of these is very expensive and not available in every centre. In the search for another prognostic factor, we decided to focus on the degree of tumour pigmentation, which is very easy to assess on indirect ophthalmoscopy. It was demonstrated that patients with amelanotic uveal melanomas (those without pigment) lived longer and the eventual spread of the neoplastic process occurred later than in patients with heavily pigmented tumours. In heavily pigmented uveal melanomas, we found features on histopathological examination that were associated with an unfavourable prognosis. In the two separate groups of uveal melanomas with different degrees of pigmentation, we observed that amelanotic tumours with a lower clinical stage had the best prognosis. (1) Background: There is a constant search for new prognostic factors that would allow us to accurately determine the prognosis, select the type of treatment, and monitor the patient diagnosed with uveal melanoma in a minimally invasive and easily accessible way. Therefore, we decided to evaluate the prognostic role of its pigmentation in a clinical assessment. (2) Methods: The pigmentation of 154 uveal melanomas was assessed by indirect ophthalmoscopy. Two groups of tumours were identified: amelanotic and pigmented. The statistical relationships between these two groups and clinical, pathological parameters and the long-term survival rate were analyzed. (3) Results: There were 16.9% amelanotic tumours among all and they occurred in younger patients (p = 0.022). In pigmented melanomas, unfavourable prognostic features such as: epithelioid cells (p = 0.0013), extrascleral extension (p = 0.027), macronucleoli (p = 0.0065), and the absence of BAP1 expression (p = 0.029) were statistically more frequently observed. Kaplan-Meier analysis demonstrated significantly better overall (p = 0.017) and disease-free (p < 0.001) survival rates for patients with amelanotic tumours. However, this relationship was statistically significant for lower stage tumours (AJCC stage II), and was not present in larger and more advanced stages (AJCC stage III). (4) Conclusions: The results obtained suggested that the presence of pigmentation in uveal melanoma by indirect ophthalmoscopy was associated with a worse prognosis, compared to amelanotic lesions. These findings could be useful in the choice of therapeutic and follow-up options in the future.

Automated summary

The degree of tumour pigmentation is an important prognostic factor for uveal melanoma. Patients with amelanotic tumours have longer survival and delayed tumour spread compared to heavily pigmented tumours. Heavily pigmented tumours also have unfavourable prognostic features. Amelanotic tumours with a lower clinical stage have the best prognosis.