From the Guidelines
No, melanomas are not always very dark, and their appearance can vary significantly, including being pink, red, purple, blue, white, skin-colored, or even colorless. The color variation of melanomas is a key aspect of their diagnosis, as outlined in the ABCDE rule, which includes Asymmetry, Border irregularity, Color variation, Diameter larger than 6mm, and Evolution or change over time 1. This rule is crucial for identifying melanomas, especially those that do not fit the typical dark pigmentation profile, such as amelanotic melanomas, which can be particularly challenging to diagnose because they lack melanin, the pigment responsible for the dark appearance of most melanomas 2.
Some key points to consider in the diagnosis of melanoma include:
- The "ugly duckling" concept, which suggests that melanomas often do not resemble other nevi in the same individual 2
- The use of dermoscopy by an experienced physician to enhance diagnostic accuracy 2
- The importance of a full-thickness excisional biopsy with a small side margin for diagnosis, processed by an experienced pathology institute 2
- The need for the histology report to follow the American Joint Committee on Cancer (AJCC) classification and include specific information such as maximum thickness, mitotic rate, and presence of ulceration 2
Given the variability in appearance and the potential for delayed diagnosis, especially for lighter-colored melanomas, it is essential that anyone noticing new or changing skin lesions has them evaluated by a healthcare provider, regardless of their color, as early detection significantly improves treatment outcomes for melanoma 1.
From the Research
Melanoma Characteristics
- Melanomas are often described as being dark brown or black in color, with the term "melanoma" derived from the Greek term for "dark tumor" 3.
- However, not all melanomas are dark, as some may be amelanotic (without pigmentation) or hypomelanotic (with limited pigmentation) 4.
Variations in Melanoma Pigmentation
- Amelanotic and hypomelanotic melanomas have a higher risk of delayed diagnosis and lower 5-year melanoma-specific survival compared to pigmented melanomas 4.
- Studies have shown that melanoma cells can produce abundant dark pigment, and that autophagy may be a common trait of invasive melanoma cells in the dermis 5.
- The presence of pigmentation in melanomas can drive an underlying immune response, with hypomelanotic melanomas showing higher levels of regression compared to amelanotic melanomas 4.
Diagnostic Features
- The ABCDE criteria (asymmetry, border irregularity, color variation, diameter > 6mm, evolving) are commonly used for melanoma education, but do not include darkness as a key feature 3.
- However, some approaches to melanoma recognition, such as the Georgia approach, include an emphasis on dark, different, and changing features, as well as a "D" for "Dark" change in the ABCDE criteria 3.
- Dermoscopy can be used to evaluate the clinicopathological and dermoscopic features of amelanotic and hypomelanotic melanomas, with common features including white structureless zones, linear looped vessels, and arborizing vessels 4.