Which type of melanoma is considered most malignant?

• A. Lentigo maligna
• B. Superficial spreading
• C. Acral lentiginous
• D. Nodular melanoma

Answer: (D)

Melanoma prognosis hinges on how deeply the cancer has invaded the skin, which is driven by its growth pattern. The most malignant form is the one that tends to invade vertically into deeper tissues very early, producing thicker tumors at diagnosis and spreading sooner to lymph nodes or distant sites. Nodular melanoma exemplifies this pattern: it often presents as a rapidly enlarging pigmented or color-varied nodule with minimal preceding radial, surface-level growth, so the depth at diagnosis is typically substantial. That early vertical invasion makes it the most aggressive subtype and carries the worst prognosis because depth correlates strongly with survival. In contrast, lentigo maligna grows slowly along the surface for many years before invading, and superficial spreading has a more pronounced radial growth phase, which can allow earlier detection and thinner lesions. Acral lentiginous can be aggressive as well, but nodular melanoma uniquely exhibits early vertical progression that drives poorer outcomes.