Adenocarcinoma and squamous cell carcinoma are two types of malignant conditions. These may present similarly but are different at the cellular level. Some adenocarcinomas are highly invasive while others are not. It is not so with squamous cell carcinoma. Both cancers are commonly found on tissue surfaces. Both are epithelial cell cancers. Cancers are thought to be due to abnormal genetic signaling which promote uncontrolled cell division. There are genes called proto-oncogene, with a simple alteration, which can be cancer causing. Mechanisms of these alterations are not clearly understood. Two hit hypothesis is an example of such a mechanism. According to cancer invasiveness, spread, and general patient outcome, both adenocarcinoma and squamous cell carcinoma need supportive therapy, radiotherapy, chemotherapy, and surgical excision for cure and palliation.
Adenocarcinoma can occur anywhere with glandular tissue. Adenocarcinoma is an uncontrolled abnormal proliferation of glandular tissue. Glands are made out of epithelial invaginations. Glands are either endocrine or exocrine. Endocrine glands release their secretions directly into the blood stream. Exocrine glands release their secretions onto an epithelial surface via a duct system. Exocrine glands may be simple or complex. Simple exocrine glands consist of a short un-branched duct which opens on to an epithelial surface. Ex: duodenal glands. Complex glands may contain a branched duct system and acinar cell arrangement around each duct. Ex: Breast tissue. Glands can be divided into two categories according to their histological appearance. Tubular glands are normally a branched system of ducts in which the blind ends are secretory. Acinar glands have bulbous cell arrangements at the end of each duct. Pituitary prolactinoma is an example of an endocrine cancer. Breast adenocarcinoma is an example of an exocrine cancer. Adenocarcinoma can spread with blood and lymph. Liver, bones, lung and peritoneum are known sites of metastatic deposits.
Squamous Cell Carcinoma
Squamous cells epithelium is found on skin, anus, mouth, small airways and a few other places. Rapidly dividing and renewing tissues are more susceptible to cancers. These cancers are, therefore, found in areas covered with squamous cells. These cancers are very visible and should not be missed. Squamous cell cancers present as ulcers with hard, raised edges. These cancers may begin as abnormal pigmentation, scar tissue and simple wounds. Long standing non healing ulcers with rapidly dividing marginal cells may turn into squamous cell cancers. It is found commonly on lips of smokers. These cancer cells rarely spread with blood and lymph flow, but there may be extensive destruction of local tissues. Squamous cell cancers may be confused with keratoacanthoma. Keratoacanthoma is a fast growing, benign, self-limiting raised lesion with keratin plugging.
Examination of a wound edge biopsy under the microscope may show cancer cells. Following diagnosis, total local excision is mostly curative.
What is the difference between Adenocarcinoma and Squamous Cell Carcinoma?
• Adenocarcinoma may occur anywhere with glandular tissue while squamous cell carcinoma mostly occurs on the skin surface.
• Adenocarcinoma arises from glands while squamous cell cancers arise from flat squamous cells.
• Adenocarcinoma can metastasize frequently while squamous cell cancers rarely metastasize.
• Local excision is mostly curative in squamous cell cancers while it may not be the case in adenocarcinoma.
Difference Between Carcinoma and Melanoma