Epignathus is a rare teratoma of the oropharynx. Epignathus as commonly used refers to any parasitic growth coming out of the mouth of the host, though the literal translation means a parasite arising from the mandible.
Epignathus is a form of oropharyngeal teratoma that arises from the palate and, in most cases, results in death. The pathology is thought to be due to unorganized and uncontrolled differentiation of somatic cells leading to formation of the teratoma. Sometimes it is also referred to as "fetus-in-fetu", which is an extremely rare occurrence of an incomplete but parasitic fetus located in the body of its twin. This tumor is considered benign but life-threatening because of its atypical features (size, location, and rate of development) and high risk of airway obstruction, which is the cause of death in 80-100% of the cases at the time of child birth.
A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone.
The oropharynx is a part of the pharynx and lies behind the oral cavity, extending from the uvula to the level of the hyoid bone. It opens anteriorly, through the isthmus of fauces, into the mouth. Its lateral wall contains the palatine tosils between the palatoglossal arch and the palatopharyngeal arche.
Fetus in fetu (or foetus in foetu) is a developmental abnormality in which a mass of tissue resembling a fetus that arises forms inside the body of another fetus. It is regarded as a parasitic twin.