Clinical Presentation of Melanoma

Clinical Presentation of Melanoma Introduction Melanoma is most curable when detected early, making clinical recognition of characteristic features essential. This section covers how melanoma presents on the skin, from subtle early changes to advanced disease, and highlights the diagnostic criteria clinicians and patients should know to catch melanoma before it spreads. Early Signs and Symptoms The earliest warning signs of melanoma often involve a change in an existing mole or the appearance of a new skin lesion. This could manifest as: A change in the shape of a mole (becoming less symmetrical) A change in the size (typically growing larger) A change in colour (becoming darker, developing multiple colours, or showing new colours) A new raised lump on the skin (particularly with nodular melanoma) The critical concept here is change over time. A mole that has remained stable for years is reassuring; a mole that has changed in appearance over weeks or months warrants clinical evaluation. The ABCDEEFG Mnemonic: A Practical Detection Tool The ABCDEEFG mnemonic is the standard framework for identifying potentially malignant lesions and is essential for both clinical practice and exam knowledge. A – Asymmetry If you mentally draw a line through the middle of the lesion, the two halves should not mirror each other. A normal benign mole is typically symmetrical; an asymmetrical appearance is concerning. B – Border Irregularity The edges of the lesion should be well-defined and smooth. In melanoma, borders often appear uneven, scalloped (wavy), or notched. Compare this to a benign mole, which typically has a clean, sharp border. C – Colour Variation A single uniform colour is reassuring. Melanomas often display multiple colours within the same lesion, such as mixtures of brown, black, red, white, or blue. The more varied the colour palette, the greater the concern. D – Diameter Greater Than 6 mm While diameter alone is not diagnostic, lesions larger than 6 mm (approximately the size of a pencil eraser) are more concerning. That said, some melanomas can be smaller, so this is a threshold rather than a strict rule. E – Evolving This refers to any change over time in size, shape, or colour. This is one of the most important and reliable warning signs. A patient noting that a mole "has changed" should always prompt evaluation. F – Elevated The lesion rises above the skin surface rather than lying flat. This is a particular feature of nodular melanoma, which grows vertically and appears as a raised bump. G – Firm The lesion feels solid and firm to the touch (rather than soft or compressible). Again, this is characteristic of nodular melanoma. It's important to recognize that not all melanomas display all seven features. Some may lack obvious colour variation or diameter over 6 mm. The ABCDEEFG criteria are guidelines, not requirements—any concerning feature warrants professional evaluation. The Ugly Duckling Sign This simple but powerful concept states that a mole that looks markedly different from a patient's other moles is more likely to be melanoma. For example, if a patient has ten brown moles and one that is black, or one that is much larger than the others, this "ugly duckling" should raise suspicion. This highlights why taking a full-body skin examination and comparing lesions to each other is valuable clinically. Major Melanoma Subtypes Melanoma is not a single disease; it presents in distinct subtypes with different growth patterns, locations, and clinical courses. Understanding these subtypes is critical. Superficial Spreading Melanoma This is the most common subtype, accounting for the majority of melanomas. It arises on intermittently sun-exposed skin (areas that receive occasional sun exposure rather than constant sun) and typically has a horizontal growth phase before becoming invasive vertically. Patients usually present because they notice a changing mole. Lentigo Maligna Melanoma This subtype originates on chronically sun-damaged skin, particularly on the face of older individuals. You will often see it in elderly patients with significant sun exposure history. The lesion develops in a background of visible solar damage (sun-induced skin changes). Acral Lentiginous Melanoma This subtype appears on the palms, soles of the feet, and under the noenails—areas where sun exposure doesn't explain the development. Importantly, acral melanoma is more common in darker-skinned populations and often lacks pigment, making it easy to miss. This is a critical point: melanoma doesn't discriminate by skin tone, and being vigilant about non-pigmented lesions in these locations is essential. Nodular Melanoma This subtype is characterized by rapid vertical growth and often appears as a raised, ulcerated (bleeding or weeping) lesion. Unlike other subtypes that have a prolonged horizontal (lateral) growth phase, nodular melanoma grows downward quickly, which is why early detection is so important for this aggressive variant. Precancerous and Early Lesions Understanding the pathway from normal skin to melanoma is essential for recognizing lesions that require close monitoring. Dysplastic (Atypical) Nevi Dysplastic nevi are abnormal moles that have histological features intermediate between normal moles and melanoma. They can serve as precursors to melanoma and warrant close monitoring. Patients with multiple dysplastic nevi have increased melanoma risk. Lentigo Maligna Lentigo maligna is a melanoma-in-situ lesion, meaning it contains malignant cells confined entirely to the epidermis (the outermost skin layer) with no invasion into deeper layers. It appears on sun-exposed skin as an irregular, often enlarging patch and must be treated because it can progress to invasive melanoma (lentigo maligna melanoma). The diagram above illustrates how dysplastic nevi can progress to melanoma and how lentigo maligna fits into this continuum. Note that not all dysplastic nevi become melanoma, but they indicate increased risk. Special Variants: Amelanotic and Acral Melanomas These subtypes deserve special attention because they challenge the traditional ABCDEEFG framework. Amelanotic Melanoma Amelanotic melanoma has little to no pigment, appearing pink, red, or skin-coloured rather than brown or black. This makes it difficult to detect using standard criteria focused on colour variation. Patients and clinicians may misdiagnose it as a benign lesion like a cyst or wart, delaying diagnosis. Acral Melanoma (Revisited) As mentioned above, acral melanoma on the palms, soles, and under nails often lacks pigment. Additionally, these locations are less commonly examined by patients or clinicians, contributing to delayed diagnosis. The key message: Any new or changing lesion should prompt evaluation, regardless of whether it is pigmented. Pigmentation is helpful when present, but its absence does not exclude melanoma. Symptoms of Advanced Disease While early melanoma may be asymptomatic beyond visible changes, advanced disease presents with systemic symptoms. Local Symptoms As melanoma grows, the lesion may develop: Itching Ulceration (breakdown of skin surface with bleeding or weeping) Bleeding These symptoms indicate an aggressive, advanced lesion. Systemic Symptoms of Metastatic Melanoma Once melanoma has spread beyond the skin, patients may experience: Loss of appetite Nausea and vomiting Fatigue Neurological symptoms (from brain metastases) Common Sites of Metastasis Melanoma spreads predictably to certain organs: Brain (a common site, often causing neurological symptoms) Liver Intestines Bone Lungs Distant lymph nodes The presence of systemic symptoms indicates stage IV disease (metastatic melanoma) with significantly worse prognosis compared to early-stage disease. This underscores the critical importance of early detection.