Conjunctival Melanoma: A Clinical Review and Update

Abstract

Conjunctival melanoma (Co-M) is an aggressive, invasive eye and eyelid cancer. Its global incidence of ~1 in a million is increasing at a rate ratio of ~1.4, but this rises sharply in over 65-year-olds. Although rare, Co-M has a devastating impact on the lives of those who develop it. Co-M is often misdiagnosed or overlooked, leading to vision loss either from the destructive effects of the tumour or side effects of therapy, facial disfigurement from radical surgery, and death from metastases. Due to its rarity, there is limited evidence for diagnosis and management; hence, there is no standardised treatment and not all cases are referred to a specialised ocular oncology centre. Recent progress in cancer immunology and genetics have revolutionised the treatment of cutaneous melanomas, which share some similarities to Co-M. Importantly, a better understanding of Co-M and its precursor lesions is urgently needed to lead to the development of novel targeted and immunotherapies both for local tumour control and disseminated disease. This review aims to provide a comprehensive clinical overview of the current knowledge regarding Co-M, its epidemiology, pathogenesis, presentation, diagnosis and recent changes in the classification of its precursor lesions, management, and recent advances in novel biological therapies for personalised treatment of this disease.

Keywords: C-MIL; conjunctival melanocytic intraepithelial lesions; conjunctival melanoma; immunotherapy; ocular oncology; targeted therapy.

Figure 1

Anterior segment photographs of low- and high-grade C-MIL (preinvasive disease) and Co-M (invasive disease). The actual grading was confirmed on histomorphological assessment.

Figure 2

Co-M histological micrographs. Haematoxylin and eosin staining photomicrographs showing an orbital exenteration specimen with Co-M at low magnification (top left), medium (top right) and higher magnification (bottom left).

Figure 3

Photomicrographs representing the C-MIL grading system. Haematoxylin and eosin section with corresponding immunohistochemistry for each of the C-MIL scoring grades [88].