What is Angiokeratoma?
Angiokeratoma is a rare vascular cutaneous disease that classically presents as distended blood vessels near the skin's surface in the form of mostly asymptomatic cardinal lesions. It is a benign condition that can produce wart-like vascular lesions that may be small or grow to larger sizes. There are five forms of Angiokeratoma: the Mibelli-type, the Fordyce-type, the solitary and multiple (papular) types, the Angiokeratoma circumscriptum, and the angiokeratoma corporis diffusum [1, 2, 3].
What Causes Angiokeratoma?
The aetiology (or causes) of angiokeratoma depend on the type and subtype, but solitary Angiokeratoma can be related to previous injury to the area where it appears [3]. Some types of Angiokeratoma are associated with increased pressure in dermal veins (eg, lower limbs) and with local changes affecting the blood vessels (eg, inguinal hernia, haemorrhoids, varicocele). Other types of Angiokeratoma such as the Fordyce-type can be related to Fabry Disease, a common hereditary condition that causes similar lesions in sun-exposed areas. Fabry Disease is one of the rarest of the inherited disorders, affecting only approximately 1 in 40,000 to 60,000 men [1, 3, 4].
What is Melanoma?
Melanoma is the most serious form of skin cancer, originates in the melanocytes, and develops from melanin, the pigment that forms colour to the skin, hair, and eye colour. It is well-known for spreading to other parts of the body quickly once it’s diagnosed. This type of cancer can develop anywhere on the body, mostly on the chest and back in men, and legs in women. Meanwhile, the face and neck are other sites where it can develop [5, 6, 7, 8, 9].
Causes of Melanoma
The exact cause of Melanoma is not well understood but typically it develops from a combination of environmental and genetic factors. Sun exposure/ultraviolet (UV) radiation from the sun or other sources, including tanning beds/lamps, is considered the main environmental risk factor as sheer UV radiation damaging the skin cells’ DNA has been identified as the initial, cancer-causing event. Sun exposure, particularly leading to sunburn, has been identified as a significant risk factor [7, 8, 9].
Genetic predisposition can also trigger the pathological regression of a benign mole. A family history of malignant Melanoma increases one’s risk of developing the disease. Subjects with certain inherited genes and traits, such as fair skin, freckling or large numbers of moles, are at increased risk. A compromised immune system can also contribute [7].
Angiokeratoma and Melanoma
Angiokeratoma and melanoma are two distinct skin conditions, each with unique characteristics. However, they can sometimes be confused due to certain overlapping features.
Differences
Angiokeratoma is a benign skin lesion characterized by vascular ectasias (dilated blood vessels) in the papillary dermis adherent to epidermal changes like hyperkeratosis and/or acanthosis. Angiokeratomas present mainly as dark red to purple-black macules and/or papules with a verrucous aspect [20]. In a dermoscopic examination, Angiokeratomas show dark lacunae (94%), whitish veil (91%), erythema (69%), peripheral erythema (53%), red lacunae (53%) and haemorrhagic crusts (53%) [21].
In contrast, Melanomas are caused by the malignant transformation of melanocytes, the cells responsible for the synthesis of the pigment melanin; such lesions can present as a change in existing moles, or as new, pigmented lesions. Whites are the group at highest risk (84.6%) and these tumours are often treated by amputation [22].
Similarities
Although the two are very different – Angiokeratomas being benign and Melanomas being malignant – they can be indistinguishable to the naked eye, and solitary angiokeratomas can often look quite melanomatous. Dermoscopy can help to distinguish them since Melanomas will show negative features such as dark lacunae and a whitish veil that Angiokeratomas will not [21].
Conclusion
In conclusion, while angiokeratomas and melanomas can sometimes appear similar, they are distinct conditions with different origins, characteristics, and treatments. Further research is needed to determine whether there is a relationship between the two contrasting conditions.