Melanoma is a potentially lethal skin cancer, and its diagnostic process requires a combination of various professional assessment methods. Early detection and accurate diagnosis are crucial for improving treatment success rates, so physicians analyze through systematic steps, from initial visual inspection to precise pathological examination, with each step aimed at excluding other skin lesions and confirming malignant features.
The diagnostic process typically includes key components such as visual observation, medical history inquiry, imaging examinations, and tissue analysis. Physicians pay special attention to critical indicators such as the shape, color, and size changes of skin lesions, and combine this with the patient's personal and family medical history for risk assessment. If melanoma is initially suspected, further pathological examination will become a decisive step in confirming the diagnosis.
Clinical assessment is the first step in diagnosing melanoma, where physicians evaluate skin lesions through visual observation and structured methods. A full-body skin examination is conducted, with particular attention to abnormal moles or newly appearing pigmented lesions, often accompanied by the "ABCDE criteria": Asymmetry, Border irregularity, Color variability, Diameter greater than 6 mm, and Evolution in shape or color. The combination of these features effectively screens for high-risk lesions.
Physicians will inquire in detail about the patient's medical history, including the development time of skin lesions, changes in appearance, history of sunburn, and family cancer history. If the patient has a family history of melanoma or immune system dysfunction, the physician may raise the alert standards. Additionally, using a dermatoscope for magnified observation can reveal structural features that are difficult to detect with the naked eye, such as reticular pigment patterns or starburst diffusion, which helps differentiate between benign and malignant lesions.
When clinical assessment reveals high-risk lesions, tissue biopsy is a key step in confirming the diagnosis. The most common examination method is excisional biopsy, where the entire lesion is removed for histological analysis. If the lesion is too large, a punch biopsy may be performed first to obtain a core tissue sample. Pathologists will observe key indicators under the microscope, such as cellular atypia, mitotic activity, and invasion depth.
Immunohistochemical staining techniques can mark specific proteins associated with melanoma, such as S-100 protein and HMB-45, aiding in differentiation from malignant peripheral nerve sheath tumors or other skin cancers. Molecular biology tests may be used to determine specific gene mutations (such as BRAF gene), which not only assist in diagnostic classification but also provide a basis for subsequent treatment options.
The development of screening tools aims to enhance early detection rates. Currently, common tools include self-skin examination guidelines and professional medical instruments. Patients are encouraged to perform regular "head-to-toe" self-examinations, paying particular attention to changes in the shape or color of existing moles. Medical institutions may use skin imaging systems to establish digital records of lesions, employing artificial intelligence algorithms to assist in tracking abnormal indicators.
Risk assessment tools such as the "ABCDEF-G" checklist, in addition to the traditional ABCDE criteria, introduce new indicators such as "Dermatologists' Erythema" and "Growth." These tools combine visual assessment with clinical symptoms to more accurately screen for high-risk lesions. Medical personnel also frequently use dermatoscopic image databases to compare and analyze with the typical features of known malignant lesions.
Differential diagnosis is a key step in the diagnostic process, requiring differentiation from various benign skin lesions. Common mimicking lesions include common nevi, actinic keratosis, and basal cell carcinoma. These benign lesions typically have clear borders and uniform colors, while malignant melanoma often presents with blurred borders and mottled colors.
Physicians must pay special attention to atypical types of lesions, such as acral melanoma, which may be confused with nail bed trauma or age spots. In Asian populations, differentiating lesions on acral skin and mucosal sites is more challenging and requires combining histological features and immunohistochemical staining results. Occasionally, differentiation from malignant peripheral nerve sheath tumors is necessary, as the latter usually lacks typical melanin deposition characteristics.
Early diagnosis can significantly improve prognosis, with a 5-year survival rate of up to 98% for stage 0 melanoma, while stage IV drops to about 20%. Early detection can be treated with local excision surgery, avoiding complex treatments after metastasis. Delayed diagnosis may lead to cancer cells penetrating the dermis, resulting in lymphatic or distant organ metastasis.
Regular skin examinations are a key strategy for early detection, with high-risk groups (history of sunburn, family history) advised to undergo professional checks every 3-6 months. Digital dermatoscopic image tracking systems can accurately capture minor changes in lesions, assisting physicians in determining whether immediate biopsy is necessary. Early diagnosis not only reduces the scope of surgery but also avoids unnecessary extensive excisions.
Particular attention should be paid to the "ABCDE criteria": Asymmetry, Border irregularity, Color variability, Diameter greater than 6 mm, and Evolution in shape or color. If moles or spots appear itchy, bleed, or enlarge rapidly, medical attention should be sought immediately.
After treatment, what regular checks or follow-ups do melanoma patients need to undergo?Post-treatment, skin examinations, blood tests (such as lactate dehydrogenase (LDH) levels), and imaging examinations (such as CT, PET-CT) are typically required every 3 to 6 months. High-risk patients may need to be monitored every 3 months for 2 to 3 years to check for signs of recurrence.
What specific recommendations are there for daily sun protection to prevent the development of melanoma?It is recommended to use broad-spectrum sunscreen with SPF 30 or higher and PA+++, reapplying every 2 hours, and wearing hats, long-sleeved clothing, and sunglasses. Avoid direct sun exposure between 11 AM and 3 PM, and regularly check for abnormal changes in the skin after sunburn.
Is it true that only moles on the skin can undergo malignant transformation?This is incorrect. While melanoma often occurs on the skin, it can also develop in mucous membranes (such as the mouth and anus) or the choroid of the eye. Atypical lesions may not exhibit the typical features of moles, thus comprehensive skin examinations must include systemic areas, including nails and soles of the feet, which are often overlooked.
Why is early diagnosis of melanoma crucial for improving treatment success rates?If melanoma only invades the skin surface (in situ cancer), the 5-year survival rate after surgical excision can be as high as 99%; however, if it has metastasized to lymph nodes or internal organs, the survival rate will drop sharply. Early diagnosis can prevent spread, making immediate medical evaluation of abnormal skin lesions critical.
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