This is the most dangerous of all the malignant skin tumors.

• A. Basal cell carcinoma
• B. Squamous cell carcinoma
• C. Malignant melanoma
• D. Actinic keratosis

Answer: (C)

The main idea is the danger of metastasis and mortality among skin cancers. Malignant melanoma is the most dangerous because it can spread quickly through lymphatic and blood routes, leading to metastases that are difficult to treat. Its prognosis depends heavily on how deep the tumor has grown (Breslow depth), whether the lesion is ulcerated, and how fast the cells are dividing. Because of this potential for early and widespread spread, melanomas are responsible for most skin cancer deaths even though they aren’t the most common type.

Basal cell carcinoma tends to stay local and very rarely spreads, so it’s not associated with high mortality. Squamous cell carcinoma can metastasize and be serious, but overall its mortality is lower than that of melanoma. Actinic keratosis is a premalignant change, not a malignant tumor itself, though it can progress to squamous cell carcinoma over time.