Definition: The word "admaxillary" is a medical term that refers to the site of an adenoid cystic malformation (ACM), also known as an adenoid sinuses, which occurs when an abnormal part of a baby's nose grows past its normal development stage and can block or close off a part of the nasal cavity. This often causes pain, difficulty breathing, and is considered an emergency. The term "adenoids" refers to small sac-like structures that develop in the lower respiratory tract (the lungs and trachea) and produce mucus to help filter out foreign particles from the air we breathe. These structures are composed of specialized cells called epithelial cells and connective tissue. When they become blocked or filled with fluids, they can form a "pseudoplasma," which is an abnormal growth of connective tissue that often leads to sinusitis. Acm (adenoid cystic malformation) is the name given to an adenoid cystic malformation, also known as an adenoid sinuses. It occurs when an abnormal part of a baby's nose grows past its normal development stage and can block or close off a part of the nasal cavity. This often causes pain, difficulty breathing, and is considered an emergency. In summary, adenoids are tiny sac-like structures that develop in the lower respiratory tract (the lungs and trachea) and produce mucus to help filter out foreign particles from the air we breathe. Acm is the name given to an adenoid cystic malformation, also known as an adenoid sinuses. It occurs when an abnormal part of a baby's nose grows past its normal development stage and can block or close off a part of the nasal cavity.