ADENOMALecture No.6

What is an adenoma?What is an adenoma?• Adenoma is a tumor of glandular

epithelium in which the cells of the tumor are arranged in a recognizable glandular structure.

• Adenoma may cause excess secretion by the affected gland, such as acidophilic pituitary adenoma resulting in an excess of growth hormone

• Adenomas are derived from the ducts and acini of glands, although the name is also used to cover simple tumors arising in solid epithelial organs.

Difference Between Adenomas and Malignant TumorsDifference Between Adenomas and Malignant Tumors

• An adenoma may form in a similar way as a malignant or cancerous tumor.

• A major difference between malignant tumors and adenomas is that adenomas do not metastasize or spread to other organs or tissues.

• Sometimes, however, adenomas develop into malignancies. When this happens, the newly malignant adenoma is called adenocarcinoma.

Symptoms related to Adenomas:Symptoms related to Adenomas:

• Symptoms related to adenomas vary widely.

• Women the use oral contraceptives may be at increased risk of liver adenomas.

• There is fever, chills, shortness of breath and a bloody cough in lung adenoma.

• Fibroadenoma typically causes no symptoms and lump may be so small that the individual is unable to detect it.

• Colon adenomas are inheritable.

Types of AdenomaTypes of Adenoma

• Papillary adenoma

• Pleomorphic adenoma

• Villous adenoma

• Tubular adenoma

• Sessile adenoma

• Pedunculated adenoma

• Cystadenoma

• Sebaceous adenoma

Sebaceous AdenomaSebaceous Adenoma

It is a small, slow-growing tumor that typically forms in the sebaceous , or oil-producing glands of the skin.

They grow mostly on the scalp, face and neck, but have been known to appear on other parts of the body.

Both men and women can develop these tumors, which generally appear at 50 years of age.

While not serious, they can sometimes indicate Muir-Torre syndrome (MTS), a serious genetic illness.

Papillary adenomaPapillary adenoma• A benign epithelial tumor in which the membrane liming the glandular tissue form papillary processes that project into the alveoli or grow out of the surface of a cavity.

• Also called adenolymphoma

• Contains intracystic papillae.

• As in hollow viscus, the proliferating epithelium may be heaped to form papillolas and the tumor becomes a papillary cystadenoma

• They are common in the ovary.

• May be few and sessile or pedunculated with fronds often complex in structure

Pleomorphic AdenomaPleomorphic Adenoma

• Pleomorphic adenoma constitutes about 60% of parotid tumors, which manifests as a salivary gland mass in young and middle-aged adults

• They have varying patterns of epithelial cells (acini, trabeculae, sheet and myoepithelial cells)

• They are usually tan-gray and well-circumscribed; some have extensions into adjacent tissue.

• Pleomorphic adenoma transform s into an aggressive carcinoma.

Villous adenomaVillous adenoma

• These polyps constitute 1/10th of colonic adenomas and are found predominantly in the rectosigmoid region.

• They are typically large, broad-based, elevated lesions that grossly display a shaggy, cauliflower-like surface.

• Villous adenoma commonly contain foci of carcinoma

• Microscopically, villous adenomas are composed of thin, tall, finger-like processes that superficially resemble the villi of the small intstines.

Villous AdenomaVillous Adenoma

Tubular AdenomaTubular Adenoma• These polyps constitute 2/3s of benign large bowel adenomas.

• It is the most common neoplastic polyp of the colon and which is most frequent in the rectum

• They are typically smooth-surfaced spheres, usually less than 2 cm in diameter, which are often attached to the mucosa by a stalk.

• Some tubular adenomas, particularly the smaller ones, are sessile.

• Microscopically, tubular adenoma exhibits closely packed epithelial tubules, which may be uniform or may be irregular and excessively branched.

Tubular AdenomaTubular Adenoma

Tubulovillous adenomaTubulovillous adenoma

• They manifest both tubular and villous features.

• These are polyps with more than 20% and less than 80% villous architecture.

• They tend to be intermediate in distribution and size between the tubular and villous forms.

• Tubulovillous polyps are also intermediate between tubular and villous adenoma in the risk of invasive carcinoma

Types of Colorectal Adenoma according to Microscopic Features:Types of Colorectal Adenoma according to Microscopic Features:

• Villous adenoma: elongated pattern of the abnormal glands. Cells form finger-like growths. It is most likely to become malignant or cancerous.

• Tubular adenoma: have glands with branched structure. It is less likely to become malignant. Most adenomas are of this type.

• Tubulovillous adenoma is a combination of the two. Seen less often.

Sessile adenomaSessile adenoma

• Polyps that are attached by a base rather than by a stalk or a peduncle.

• Sessile adenomas are structures with large, broad bases.

CystadenomaCystadenoma• Cystadenoma or cystic adenomas are

benign tumors which grows into the subjacent connective tissue, with progressive budding of the epithelium that results in new acini which become nipped off from the parent acini

• Types of Cystadenoma:

• Serous Cystadenoma – makes up 25% of all ovarian tumors. Most of them are bilateral.

• Mucinous Cystadenoma – accounts for 20%of all ovarian tumors. It can reach a very large size and is typically multilocular, 25% bilateral.

Mucinous CystadenomaMucinous Cystadenoma

Pedunculated adenomaPedunculated adenoma

• Pedunculated polyps has a stemlike connection or having a stalk

• Pedunculated polyps vary in size from a few mm to 3 or more cms.

• Microscopically, there is proliferation of tubular colonic glands, with varying amounts of dysplasia

• Few have frankly malignant change

Adenomatous polyposis coli (APC)Adenomatous polyposis coli (APC)

• An inherited disorder characterized by the development by myriad polyps in the colon beginning in late adolescence or early adulthood.

• The gene is located on chromosome 5

• Untreated, the condition may lead to colon cancer.

APCAPC

Glandular Adenomas can be diagnosed by:Glandular Adenomas can be diagnosed by:

• Colonoscopy: Doctors insert a probe containing a camera through the anus in order to visualize the inner surface of the colon and rectum. Any tissue jutting out abnormally is removed during the procedure and then sent to a pathologist for microscopic analysis.

• Other imaging techniques, such as CT Scan or an Air-contrast barium enema can be done.

Three Types of Adenomas that can be seen during Colonoscopy: Three Types of Adenomas that can be seen during Colonoscopy:

• Sessile adenoma are large structures with broad bases.

• Flat adenomas have also large bases connected to the inner wall of the GIT, but these growths typically have a diameter at least 2 times longer than the height.

• Pedunculated adenomas are mushroom-shaped with a narrow stalk connecting the inner intestinal surface to the growth.

Fibroadenoma – Female breastFibroadenoma – Female breast

Breast AdenomaBreast Adenoma

• A breast adenoma or fibroadenoma is a typical lump of few cms. in diameter, but may grow if a woman becomes pregnant.

• The existence of a breast adenoma is not a precursor to developing breast cancer, although it has been found out to indicate a slightly higher risk for developing malignant tumors later in life.

• Removal by surgery may be necessary if a tumor associated with breast adenoma continues to grow.

FIBROADENOMAFIBROADENOMA

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• Quiz on Adenoma

• Assignment: Read on Neoplasms