Melanoma is a serious form of skin cancer, often recognized by its dark, irregular appearance. However, not all melanomas present with noticeable dark pigment. These less pigmented forms are medically termed “amelanotic melanoma,” and their atypical appearance can lead to them being overlooked. Recognizing this potentially aggressive skin cancer requires understanding that melanoma can appear light.
What is Amelanotic Melanoma?
Amelanotic melanoma is a type of skin cancer where the malignant cells produce little to no melanin, the dark pigment that gives most moles their color. This lack of pigment is why these lesions appear light, often skin-colored, pink, red, or even clear. While less common, amelanotic melanoma accounts for approximately 2% to 20% of all melanoma cases.
Despite their lighter appearance, amelanotic melanomas are still a type of melanoma and can be aggressive, sometimes growing quickly within weeks or months. They can develop anywhere on the body, including sun-exposed areas like the head and neck, but also in less obvious locations such as under the nails or on mucous membranes.
How to Spot Amelanotic Melanoma
Identifying suspicious lesions that might be amelanotic melanoma requires careful observation, as they often do not follow the typical ABCDE rules (Asymmetry, Border irregularity, Color variation, Diameter, Evolving) associated with pigmented melanomas. Instead, attention should focus on non-pigmented signs or changes in skin lesions. Amelanotic melanomas may appear as persistent red, pink, or skin-colored macules, papules, or nodules with irregular borders.
The “C” for color in the ABCDEs is particularly challenging for amelanotic melanoma, as they lack the usual dark hues. Instead, look for lesions changing in size, shape, or texture, or any new symptom like bleeding, itching, or pain. A persistent non-healing sore, a rapidly growing pink bump, or a subtle red patch that does not resolve should prompt concern. Physicians may also use the “3 R’s” mnemonic (Red, Raised, Recent change) for screening.
Diagnosis and Treatment Options
Medical professionals diagnose amelanotic melanoma through a thorough skin examination, often aided by dermoscopy, which uses a specialized magnifying device to examine skin lesions more closely. Dermoscopy can reveal specific vascular patterns, such as milky-red areas or irregular dotted vessels, which are characteristic of amelanotic melanoma even without pigment. However, a definitive diagnosis relies on a biopsy.
An excisional biopsy, where the entire suspicious lesion and a small margin of surrounding healthy tissue are removed, is the standard for diagnosis. The removed tissue is then examined under a microscope by a dermatopathologist to confirm cancerous cells and determine features like tumor thickness and mitotic rate. Once diagnosed, treatment for amelanotic melanoma involves surgical removal of the tumor. For advanced cases where melanoma has spread, additional treatments may include radiation therapy, chemotherapy, targeted therapy (which blocks specific cancer growth pathways), or immunotherapy (which boosts the body’s immune response against cancer cells).
Prognosis and Prevention
The prognosis for amelanotic melanoma is influenced by early detection. Factors such as the tumor’s thickness at diagnosis (Breslow thickness), its location, and whether it has spread to lymph nodes or distant sites all impact the long-term outlook. Due to their atypical appearance, amelanotic melanomas are sometimes diagnosed at a more advanced stage, which can affect the prognosis.
Preventing amelanotic melanoma involves sun protection measures. This includes applying broad-spectrum sunscreen with an SPF of 30 or higher, wearing protective clothing, seeking shade during peak sun hours, and avoiding tanning beds. Regular self-skin exams also identify any new or changing spots, regardless of color. Professional skin checks by a dermatologist, particularly for individuals with risk factors like fair skin, a history of significant sun exposure, or a family history of melanoma, are recommended for early detection.