Epithelioma is an abnormal growth

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 of the epithelium

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

, which is the layer of tissue that covers the surfaces of organs and other structures of the body.

Classification

Epitheliomas can be benign growths or malignant carcinomas

Carcinoma

Carcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...

. They are classified according to the specific type of epithelial cells that are affected.

The most common epitheliomas are basal cell carcinoma

Basal cell carcinoma

Basal-cell carcinoma is the most common type of skin cancer. It rarely metastasizes or kills. However, because it can cause significant destruction and disfigurement by invading surrounding tissues, it is still considered malignant. Statistically, approximately 3 out of 10 Caucasians may develop a...

 and squamous cell carcinoma

Squamous cell carcinoma

Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...

(skin cancers).

Prognosis

The prognosis varies dramatically, depending on the type and stage at the time of treatment. However, the most common epitheliomas are very easily treated and rarely result in death.