Table 1.

Comparison of cutaneous and ocular melanoma characteristics

	Cutaneous melanoma	Ocular melanoma
Origin	Melanocytes located in the basal layer of the epidermis of the skin	Uveal - melanocytes situated in the stroma of the uveal layer of the eye
		Conjunctival - melanocytes situated in the basal layer of the conjunctiva
Rate per million [1]	153.5	6 all ocular melanomas
		4.9 uveal melanoma
		0.4 conjuctival melanoma
Male vs. female rate per million [1]	193.7 vs. 125.2	6.8 vs. 5.3 for all ocular melanomas
		5.7 vs. 4.4 for uveal melanomas
		0.4 both genders for conjunctival melanoma
Trends in incidence	Rising [81,117]	Uveal melanoma - stable [6]
		Conjunctival melanoma - rising [7,76,80]
Role of a UV light as risk factor	Well supported [118]	Still uncertain
Mean age	55.3 years [119]	Uveal melanoma - 58 years [8]
		Conjunctival melanoma - 57.4 years [77]
White:black ratio	16:1 [1]	8-10:1 for all ocular melanomas [1]
		2.6:1 for conjunctival melanoma [5]
Metastasizing	Lymphogenous and hematogenous	Uveal - hematogenous
		Conjunctival - lymphogenous and hematogenous
Most common sites of metastases	skin (13–38%)	Uveal
	distant lymph nodes (5–34%)	Liver (93%)
	distant subcutaneous tissues (32%)	Lung (24%)
	lung (18–36%)	Bones (16%) [45]
	liver (14–20%)	Conjunctival
	CNS (2–20%)	Lymph nodes (cervical, preauricular, parotid and submandibular)
	bone (4–17%) [120]	Lungs, liver, skin and brain [75,77,88]
Five-year survival	80.8% [119]	81.6% - uveal melanoma [6]
		86.3% - conjunctival melanoma [77]
Treatment	91.5% surgery only [119]	Uveal - 28.3% surgery only 62.5% radiotherapy only [6]
		Conjunctival - nowadays mostly surgical excision combined with adjuvant therapy
Common genetic mutations	BRAF	GNAQ and GNA11 - uveal melanoma [102,103]
	CDKN2A	BAP1 - metastasizing uveal melanoma [110]
	NRAS [121]	BRAF - iris and conjunctival melanoma [107,108]