What is the term for the growth of abnormal skin cells?

The term for the growth of abnormal skin cells is "tumor." In the context of the integumentary system, a tumor refers to an abnormal mass of tissue that can arise from various types of cells in the skin. Tumors can be benign (non-cancerous) or malignant (cancerous), but they are characterized by uncontrolled cell growth. This abnormal proliferation can occur in various skin layers and may present in different forms, such as moles or skin cancers.

Lesions, while they can be related to abnormal growth, refer more broadly to any abnormal change in the structure of skin, including rashes, sores, or scars. A mass is a general term that indicates a localized swelling or aggregation of tissue but does not specifically relate to the fundamental abnormality of skin cells. Cysts are sac-like structures that can develop in the skin but are typically filled with fluid or semisolid material rather than indicating a growth of abnormal cells. Thus, "tumor" is the precise term that captures the essence of abnormal cell growth in the skin.