A mass of histologically normal tissue found in an abnormal location is called a:

A choristoma (also called heterotopia) is defined as a mass of normal, mature, histologically correct tissue found in an abnormal anatomical location. For example, salivary gland tissue found in the middle ear or lymph node represents a choristoma. A hamartoma, in contrast, is a disorganized but non-neoplastic mass of tissue elements normally found in that site. An odontoma is a benign odontogenic tumor. Ameloblastoma is a benign but locally aggressive odontogenic tumor arising from enamel organ epithelium.