Adenoid cystic carcinoma: A type of cancer that most often develops in the salivary glands of the head and neck. It may arise in other sites such as the skin, lacrimal gland, trachea, breast, cervix and prostate. Adenoid cystic carcinoma (ACC) has a characteristic appearance under the microscope. Abnormal “nests” or cords of certain cells (epithelial cells) can be seen to surround or infiltrate ducts and glandular structures. These structures are typically filled with a mucous-like material or contain abnormal fibrous membranes (hyaline membranes).
ACC is an unusual tumor. It is slow-growing but relentless. It tends to be locally invasive and infiltrate the “sheaths” or coatings surrounding nerve fibers (perineural spaces). ACC often recurs years later at the site where the tumor first arose or it may metastasize. Unlike most carcinomas, it seldom metastasizes to nearby lymph nodes but rather to distant sites. The lung is the most common site of metastasis, with the liver second. Bone metastases indicate a poor prognosis .
Treatment usually involves surgery to resect (remove) the tumor. Postoperative radiotherapy may help prevent local recurrence. Chemotherapy may slow the tumor but no chemotherapy has yet been found that is effective in destroying it.
Adenoids: A lump of lymphoid tissue of varying size, located behind the nose in a space called the nasopharynx.
- Adenoids and Tonsils
These celebrated structures (adenoids and tonsils) in the back of the throat are composed of tissue similar to lymph nodes or “glands.”
Adenoma: A benign tumor that arises in or resembles glandular tissue. If an adenoma becomes cancerous, it is called an adenocarcinoma.
Adenomyoma: A nodule that forms around tissue of the inner uterus (endometrial tissue) as a result of adenomyosis. See adenomyosis.
Adenomyosis: A common, benign condition of the uterus in which the endometrium (the inner uterus) grows into the adjacent myometrium (the uterine musculature located just outside the endometrium). The myometrium may respond to this intrusion with muscular overgrowth. If an island of endometrial tissue is contained within the myometrium, it forms an adenomyoma. Also known […]