Adenosquamous carcinoma
Refers to a mixed tumor containing both adenocarcinoma and squamous cell carcinoma, wherein each of these cell types comprise at least 10% of the tumor volume. Anaplastic carcinoma
Refers to a heterogeneous group of high-grade carcinomas that feature cells lacking distinct histological or cytological evidence of any of the more specifically differentiated neoplasms. These tumors are referred to as anaplastic or undifferentiated carcinomas. Large cell carcinoma
Composed of large, monotonous rounded or overtly polygonal-shaped cells with abundant cytoplasm. Small cell carcinoma
Cells are usually round and are less than approximately 3 times the diameter of a resting lymphocyte and with little evident cytoplasm. Occasionally, small cell malignancies may themselves have significant components of slightly polygonal and/or spindle-shaped cells.There are a large number of rare subtypes of anaplastic, undifferentiated carcinoma. Some of the more well known include the lesions containing pseudo-sarcomatous components: spindle cell carcinoma (containing elongated cells resembling connective tissue cancers), giant cell carcinoma (containing huge, bizarre, multinucleated cells), and sarcomatoid carcinoma (mixtures of spindle and giant cell carcinoma). Pleomorphic carcinoma contains spindle cell and/or giant cell components, plus at least a 10% component of cells characteristic of more highly differentiated types (i.e. adenocarcinoma and/or squamous cell carcinoma). Very rarely, tumors may contain individual components resembling both carcinoma and true sarcoma, including carcinosarcoma and pulmonary blastoma. A history of cigarette smoking is the most common cause of large cell carcinoma.
Microscopic examination by a pathologist is then necessary to identify molecular, cellular, or tissue architectural characteristics of epithelial cells. Types
Oral: Most oral cancers are squamous-cell carcinoma
Lung: Carcinoma comprises >98% of all lung cancers. Breast: Nearly all breast cancers are ductal carcinoma. Prostate: The most common form of carcinoma of the prostate is adenocarcinoma. Colon and rectum: Nearly all malignancies of the colon and rectum are either adenocarcinoma or squamous cell carcinoma. Pancreas: Pancreatic carcinoma is almost always of the adenocarcinoma type and is highly lethal. Ovaries: One of the most deadly forms due to late detection.Some carcinomas are named for their or the putative cell of origin, (e.g.hepatocellular carcinoma, renal cell carcinoma). Staging
Staging of carcinoma refers to the process of combining physical/clinical examination, pathological review of cells and tissues, surgical techniques, laboratory tests, and imaging studies in a logical fashion to obtain information about the size of the neoplasm and the extent of its invasion and metastasis. Carcinomas are usually staged with Roman numerals. In most classifications, Stage I and Stage II carcinomas are confirmed when the tumor has been found to be small and/or to have spread to local structures only. Stage III carcinomas typically have been found to have spread to regional lymph nodes, tissues, and/or organ structures, while Stage IV tumors have already metastasized through the blood to distant sites, tissues, or organs.