Carcinoma

In medicine, carcinoma is any cancer that arises from epithelial cells. It is malignant by definition: carcinomas invade surrounding tissues and organs, and may spread to lymph nodes and distal sites (metastasis). Carcinoma in situ (CIS) is a pre-malignant condition, in which cytological signs of malignancy are present, but there is no histological evidence of invasion through the epithelial basement membrane.