Normal tissue growing in an ABNORMAL location is called:

Correct answer: B. Choristoma

• A. A hamartoma is an abnormal MIXTURE of normal tissues in their CORRECT LOCATION — not normal tissue in an abnormal location.
• B. CHORISTOMA (hamartoma of ectopic tissue) is defined as normal tissue found in an ABNORMAL LOCATION. Examples: oral choristoma with ectopic bone (osseous choristoma) on the tongue, gastric tissue (Meckel's diverticulum), or brain tissue in other locations. Contrast with HAMARTOMA = normal tissue in normal location but abnormal arrangement.
• C. A cyst is a pathological cavity lined by epithelium — it is not defined by ectopic tissue location.
• D. A teratoma contains tissue from all three germ layers (ectoderm, mesoderm, endoderm) in an abnormal location — it is a germ cell tumor, not simply ectopic normal tissue.