• A benign (not cancer) growth made up of an abnormal mixture of cells and tissues normally found in the area of the body where the growth occurs.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• A benign and excessive tumor-like growth of mature cells and normal tissues which grow in a disorganized pattern.
  NCI
  U.S. National Cancer Institute, 2021
• A disordered proliferation of mature tissues that is native to the site of origin, e.g., exostoses, nevi and soft tissue hamartomas. Although most hamartomas are benign, some histologic subtypes, e.g., neuromuscular hamartoma, may proliferate aggressively such as mesenchymal cystic hamartoma, Sclerosing epithelial hamartoma, Sclerosing metanephric hamartoma.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• A focal malformation resembling a neoplasm, composed of an overgrowth of mature cells and tissues that normally occur in the affected area.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• An excessive but focal overgrowth of cells and tissues native to the organ in which it occurs.
  CDISC Terminology
  Clinical Data Interchange Standards Consortium (CDISC), 2021
• A hamartoma (from Greek hamartion �bodily defect�) is a benign (noncancerous) tumorlike malformation made up of an abnormal mixture of cells and tissues found in areas of the body where growth occurs. It is considered a developmental error and can occur at a number of sites.
  Medscape
  WebMD, 2025
• Hamartoma, benign tumourlike growth made up of normal mature cells in abnormal number or distribution. While malignant tumours contain poorly differentiated cells, hamartomas consist of distinct cell types retaining normal functions. Because their growth is limited, hamartomas are not true tumours...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025