A skin tumor is a type of tumor that develops on the epidermis. Tumors, including skin tumors, are groups of abnormal cells that grow, called neoplasm. People often associate a skin tumor with cancer, but in fact tumors don’t have to be cancerous, and the vast majority are not. Tumors are usually classed in three different groups: benign, pre-malignant, and malignant. Only malignant tumors are actually cancerous.
The different terms used can be a bit confusing, but they are essentially greater levels of specificity. A neoplasm is a group of abnormal cells, but these abnormal cells don’t necessarily form a lump. When a neoplasm forms a lump it is known as a tumor. If that tumor forms on the epidermis, it is known as a skin tumor. If the skin tumor that forms is malignant, meaning it has uncontrolled growth, invades nearby tissue, and may even spread to other parts of the body, then it is known as skin cancer.
A benign skin tumor will never transform into skin cancer, and so poses no cause for concern except perhaps an aesthetic one. Moles on the skin are a good example of this sort of skin tumor, and while many people get them removed because they find them unsightly, only some moles are cancerous. Uterine fibroids are another good example of a benign skin tumor. Some other forms of benign skin tumor include seborrheic keratoses, which look like small lesions stuck to the skin, acrochordons, more commonly known as skin tags, epidermoid or sebaceous cysts, which are round, keratin lined cysts of the skin, and dermatofibroma, which are small nodules that form on the skin as an inflamed circular area.
Pre-malignant skin tumors are not yet cancerous, because they don’t invade surrounding tissue. They are not, however, benign, because over time they will become malignant and demonstrate the same destructive properties that cancerous cells have. One common form of pre-malignant cancer is carcinoma in situ, where the cells are neoplastic, and do continue to multiply, but do not leave their confined space.
The most commonly thought of type of skin tumor is a cancerous skin tumor, as these are the most dangerous. Malignant skin tumors will, if left alone, likely spread throughout the body, metastasizing and eventually killing the host. Malignant skin tumors are treated with a wide range of treatments to try to destroy them, including chemotherapy, invasive surgery, and radiation therapy. Skin tumors often will spread first to surrounding lymph nodes, and in this case those lymph nodes need to be removed as well. So long as malignant skin tumors are detected early, treatment is usually quite effective and not terribly invasive or destructive.
Some things are looked at and treated as a skin tumor, when they are not, strictly speaking, a tumor of the skin. Lipoma is an excellent example of this, as it is subcutaneous, made up of adipocytes, create a hard nodule that can create an unsightly bump in the skin itself. Lipomas are usually extracted via minor surgery, with little to no scarring as a result.