By Dr Ananya Mandal, MD
Adenocarcinoma commonly affects the lungs and the colon. Each of the organs when affected by adenocarcinoma show a different histopathology.
Colon cancer histopathology
Colon adenocarcinoma is the most common type of gastrointestinal cancer, and has an incidence of about 140,000 cases each year in the United States, according of the National Cancer Institute.
The cancer begins in the cells of glandular structures in the inner layer of the colon and spreads to the walls of the colon and then via blood and lymphatic channels to other organs. Colon cancer stems from colon polyps that turn cancerous, and individuals who develop polyps are at the highest risk of colon cancer.
Biopsy is the surest method of diagnosing this cancer. A cancerous colon polyp is prepared and stained and then looked at under the microscope. Most of the colon cancers are adenocarcinoma because the colon has numerous glands within the tissue.
Normal colonic glands tend to be simple and tubular in appearance. They have mucus secreting goblet cells and water absorbing cells. These glands normally help absorb water from the feces back into the blood and secrete mucus into the colon lumen to lubricate the feces.
The adenocarcinoma appears as a mass that looks of a different color than the surrounding tissue. Bleeding from the tumor is often apparent. Under the microscope a glandular structure, similar to the healthy normal surrounding glands may be seen. If they look very similar, this is a low grade tumor. If they are haphazard and numerous snaky tubes of glands throughout the walls of the colon, it is termed a high grade tumor with poor differentiation. The cells have a large nucleus with prominent nucleoli and increased mitoses, or cell divisions.
Lung cancer histopathology
Lung adenocarcinoma is the most common kind of lung cancer, both in smokers and nonsmokers and in people under age 45. In fact adenocarcinoma accounts for about 40 percent of primary lung cancers in female smokers and 30 percent in male smokers. Among non-smokers it is 60 percent in males and 80 percent in females. This disease also is more common among Asian populations and those of Asian descent.
Lung adenocarcinoma is a non-small cell lung cancer that develops in the peripheral portion of the lungs or margins of the lungs. Lung adenocarcinoma cells form recognizable glandular patterns. These are slow growing tumors.
The cancer tissues are visualized under the microscope from the washings of the bronchial secretions, sputum or from lung biopsy. Adenocarcinoma of the lung tends to stain mucin positive as it is derived from the mucus producing glands of the lungs. The tumors may be well differentiated (low grade) resembling surrounding normal glandular structure or appear poorly differentiated, high grade and appear abnormal compared to surrounding tissues.
Adenocarcinoma in the cervix
Adenocarcinoma is the second most common sub-type of cervical cancer, making up about 15 to 20 percent of all cervical cancers. Cervical adenocarcinoma arises within glands located in the endocervix.
Most women diagnosed with cervical adenocarcinoma are in middle ages and about 20 percent are over age 65. The cause of cervical adenocarcinoma is not completely known but most are thought to be caused by human papillomavirus infections or HPV.
Diagnosis is made by the Pap test or by taking a biopsy of the cancer tissues. Most cervical adenocarcinomas are characterized by an abnormal mass or growth on the cervix. This can be detected using a colposcopic examination. The Pap test is done by scraping or brushing the surface lining of the cervix to gather cells. If the cells are suspected to be abnormal a biopsy is advised.
Adenocarcinoma of the pancreas
Around 95% of pancreatic cancers are ductal adenocarcinomas. Ductal adenocarcinomas have a mean diameter of 2.5 cm. These commonly arise in the head of the pancreas. When surgically removed most of the pancreatic adenocarcinomas have spread beyond the pancreas, either by direct extension or direct spread, lymphatic and or blood related spread.
Diagnosis may be made using tissue samples from the cancer using a fine needle. This is called fine needle aspiration cytology or FNAC. Distinguishing among pseudocysts and serous and mucinous adenomas and carcinomas is a challenge on fine needle aspiration cytology.
Other organs affected by adenocarcinoma include:
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)