A nurse is caring for a client who states he has a nevus that has increased in size and changed in color. On examination, the nurse notes an elevated two centimeter lesion that is dark brownish-black in color with irregular borders. The nurse should recognize that these findings are consistent with which of the following medical diagnoses?

Choice A reason: Malignant melanoma is a type of skin cancer that often presents as a mole that changes in size, color, and appearance. The description of the lesion being dark brownish-black with irregular borders is characteristic of malignant melanoma. This type of cancer can metastasize rapidly and requires prompt medical intervention for diagnosis and treatment.

Choice B reason: Basal cell carcinoma typically appears as a pearly or waxy bump, often with visible blood vessels. It is less likely to present as a dark, irregularly bordered lesion. Basal cell carcinoma is generally slow-growing and less likely to change rapidly in size and color compared to malignant melanoma.

Choice C reason: Squamous cell carcinoma often presents as a red, scaly, and thickened patch on the skin, sometimes with a crusted or ulcerated surface. While it can change in size, it does not typically appear as a dark, irregularly bordered lesion. Squamous cell carcinoma usually develops in areas of the skin exposed to the sun and has a different presentation compared to malignant melanoma.

Choice D reason: Kaposi's sarcoma presents as purplish, reddish-blue, or dark brown lesions that are often flat or slightly raised. These lesions are common in clients with AIDS but are usually smaller and less likely to have irregular borders compared to malignant melanoma. The description provided is more consistent with malignant melanoma than Kaposi's sarcoma.