Conjunctival melanoma Melanomas of the conjunctiva (the transparent sheath that covers the eyeball and the inner surface of the eyelid) are very rare; occurring in less than one individual per million people every year, most commonly in the Caucasian population. These melanomas usually appear in adulthood with the mean age of incidence being around 60 years. Conjunctival melanomas can appear spontaneously or following the development of intra-epithelial neoplasia, rarely they develop from an already existing mole or naevus.
One fifth of patients develop metastatic disease within 2-3 years of diagnosis with an estimated one third of these patients dying within ten years of the onset of symptoms. Approximately half of all conjunctival melanomas recur.
Standardised documentation to record the presentation and treatment of conjunctival melanomas has been developed by the Liverpool Ocular Oncology Centre (LOOC) in order to facilitate better collection of data for this rare tumour in multicentre studies. This system was used to successfully audit treatment of conjunctival melanomas at the LOOC.
Studies of the aetiology and pathogenesis of conjunctival melanoma have been hampered by the rarity of the disease resulting in many investigations analysing a limited number of patient samples. Despite this several genetic studies have revealed the presence of frequent BRAF mutation; in addition, the common, non-random genetic abnormalities of chromosomes 3, 6 and 8, that occur in uveal melanomas, are not found in conjunctival melanoma suggesting, a more similar pathogenesis to cutaneous melanoma. Studies performed by LOORG demonstrated common amplification of CDKN1A and RUNX2 in primary conjunctival melanomas. In metastases amplification of MLH1, TIMP2 and chromosome 20q were also common in addition to deletion of MGMT and ECHS1.
One fifth of patients develop metastatic disease within 2-3 years of diagnosis with an estimated one third of these patients dying within ten years of the onset of symptoms. Approximately half of all conjunctival melanomas recur.
Standardised documentation to record the presentation and treatment of conjunctival melanomas has been developed by the Liverpool Ocular Oncology Centre (LOOC) in order to facilitate better collection of data for this rare tumour in multicentre studies. This system was used to successfully audit treatment of conjunctival melanomas at the LOOC.
Studies of the aetiology and pathogenesis of conjunctival melanoma have been hampered by the rarity of the disease resulting in many investigations analysing a limited number of patient samples. Despite this several genetic studies have revealed the presence of frequent BRAF mutation; in addition, the common, non-random genetic abnormalities of chromosomes 3, 6 and 8, that occur in uveal melanomas, are not found in conjunctival melanoma suggesting, a more similar pathogenesis to cutaneous melanoma. Studies performed by LOORG demonstrated common amplification of CDKN1A and RUNX2 in primary conjunctival melanomas. In metastases amplification of MLH1, TIMP2 and chromosome 20q were also common in addition to deletion of MGMT and ECHS1.
