Cutaneous Malignant Melanoma

Cutaneous malignant melanoma (MM) arises from normal epidermal melanocytes or pre-existing nevus cells; less common than other skin cancers but highly malignant, rapidly progressive, ominous, very poor prognosis.

Common Symptoms

Scale; depigmentation; nodule; nevus cells; nail/plate changes; melanuria

Causes and Pathogenesis

Etiology: (1) Nevus transformation: MM from junctional/dermal nevi; ~1/3 no prior nevus; warning signs: rapid growth, color change, irregular pigment halo, itching, scaling, ulceration, bleeding, satellite nodules, regional node enlargement. (2) UV radiation (290-320nm): increases melanocyte number and quality; higher in sunnier/agricultural/coastal areas; lentigo-maligna MM linked to direct sun; nodular MM on non-sun sites possibly via solar-circulating factor. (3) Race: whites >> Blacks. (4) Genetic: familial, earlier onset ~10y; xeroderma pigmentosum 50%. (5) Trauma/irritation: scalp/palms/soles; prior mole removal; 10-60% trauma history. (6) Virus-like particles seen. (7) Immunity: older age; spontaneous regression. Pathology: atypical melanocytes forming nests at dermoepidermal junction; mitoses; eosinophilic owl-eye nucleoli. Types: lentigo maligna, superficial spreading (Pagetoid), nodular, acral lentiginous. Grading: Clark levels I-V (invasion depth); Breslow thickness (<=0.75, 0.76-1.5, 1.51-3.0, 3.01-4.5, >4.5mm); thicker = worse prognosis.

Treatment

Surgery, drug, supportive therapy

Preventive Measures

Avoid sun; sunscreen = primary prevention esp. high-risk groups; public/professional education; early detection/diagnosis/treatment.

Department to Visit

It is recommended to visit the Dermatology department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.