is any malignant cancer
that arises from epithelial cells
. Carcinomas invade surrounding tissues and organs and may metastasize
, or spread, to lymph nodes
and other sites.
Carcinoma in situ (CIS) is a pre-malignant condition, in which some cytological signs of malignancy are present, but there is no histological evidence of invasion through the epithelial basement membrane.
Classification of carcinoma
Carcinoma, like all neoplasia
, is classified by its histopathological appearance. Adenocarcinoma
and squamous cell carcinoma
, two common descriptive terms for tumors
, reflect the fact that these cells may have glandular
or squamous cell appearances respectively. Severely anaplastic
tumors might be so undifferentiated that they do not have a distinct histological appearance (undifferentiated carcinoma).
Sometimes a tumour is referred to by the presumptive organ of the primary (eg carcinoma of the prostate) or the putative cell of origin (hepatocellular carcinoma, renal cell carcinoma).
Types of carcinoma by ICD-O Code
Types of lung carcinoma
Staging and grading
The staging of cancers is the extent of spread of the neoplasm. Grading is the system used to record the tumors degree of differentiation from the parent tissue. High grade shows little differentiation and the prognosis is therefore poor.
Carcinomas, like all cancers, are staged according to the extent of disease. The UICC/AJCC TNM system is often used, however for some common tumors, classic staging methods (such as the Dukes classification for colon cancer) are still used.