What type of cancer is melanoma and where does it arise?

• A. Malignancy of lymphoid tissue in nodes.
• B. Malignancy of plasma cells.
• C. Adenocarcinoma of lung.
• D. Malignancy of melanocytes, most commonly occurring in skin.

Answer: (D)

Melanoma is a cancer that arises from melanocytes, the pigment-producing cells that sit in the epidermis of the skin. These cells give skin its color, and when they turn malignant, the resulting tumor is melanoma. It is most common in the skin because that’s where the majority of melanocytes reside, though it can also appear in other pigmented tissues like the eyes or mucous membranes.

The other descriptions point to different cancers: lymphoma is a malignancy of lymphoid tissue, myeloma involves plasma cells, and adenocarcinoma of the lung is a cancer arising from glandular cells in the lung. The statement that best fits melanoma is that it is a malignancy of melanocytes, most commonly in the skin.