Melanoma is the most dangerous form of skin cancer, arising from pigment-producing cells called melanocytes. While most melanomas appear as dark, irregularly shaped spots, a less common variant lacks this typical dark coloration. This non-pigmented form is challenging to identify, often leading to delayed diagnosis and more advanced disease at the time of detection. Understanding the subtle signs associated with this variant is paramount for early intervention.
Defining Amelanotic Melanoma
Amelanotic melanoma (AM) is a subtype of melanoma characterized by a significant reduction or complete absence of the dark pigment melanin. This lack of color means the lesion does not appear brown or black like most other melanomas. AM accounts for a small percentage, typically between two and 20 percent, of all melanoma cases.
The biological reason for this absence of pigment is that the malignant melanocytes either fail to produce mature melanin granules or cannot retain the pigment they produce. This cancer is considered highly aggressive partly because its unusual appearance often leads to misdiagnosis or a delay in seeking medical evaluation.
Common Symptoms and the Itching Question
The question of whether amelanotic melanoma itches is common, and the answer is that it certainly can. Itching is a frequent symptom associated with both pigmented and non-pigmented melanomas, though its presence is not universal. Persistent or new-onset itching in an unusual skin spot should prompt a professional evaluation, regardless of the lesion’s color.
Beyond itching, patients with AM may experience other localized symptoms that signal a change. These include tenderness or pain upon touching the area, which can indicate irritation or invasion of nearby tissues. A significant warning sign is a spot that bleeds, oozes, or develops a crust that does not heal within three weeks or repeatedly returns.
Visual Characteristics of Amelanotic Lesions
Because AM lacks the dark color typical of melanoma, the traditional ABCDE criteria are often unreliable for initial identification. Instead of being black or brown, the lesions frequently appear as patches or nodules that are pink, red, skin-colored, or reddish-purple. Some AM lesions may have faint tan, gray, or light brown pigmentation only at the edges or in small, irregular areas.
This colorless appearance means AM can easily mimic benign conditions like a scar, a persistent patch of dermatitis, or a wart. When the lesions are raised, they often look like other growths, such as basal cell carcinoma or a pyogenic granuloma. For non-pigmented lesions, doctors often use additional recognition strategies, such as the EFG rule, to aid in detection.
The EFG Rule
The EFG criteria stand for Elevation, Firmness, and Growth, which are important features when a lesion is not dark. An elevated lesion is raised above the surrounding skin, and a firm lesion feels hard or dense when pressed. Growth refers to a lesion that is visibly enlarging over weeks or months. Any non-pigmented spot that is growing quickly or stands out from other nearby moles—known as the “ugly duckling” sign—warrants immediate attention.
Next Steps in Diagnosis and Management
If a suspicious lesion is noticed, especially one that is changing, growing, or exhibiting symptoms like tenderness or bleeding, immediate consultation with a dermatologist is necessary. Diagnosis begins with a thorough full-body skin examination and close inspection using a handheld device called a dermatoscope. Dermoscopy allows the physician to examine the lesion’s structure, focusing on internal vascular patterns that can indicate malignancy, even without pigment.
The only definitive way to confirm an AM diagnosis is through a skin biopsy, where tissue is removed and analyzed microscopically by a pathologist. This step is mandatory for determining the tumor’s depth and confirming the presence of cancerous melanocytes. Management for AM, like other forms of melanoma, typically involves surgical excision to remove the tumor and a margin of surrounding healthy tissue.