Hamartoma: A rare developmental disorder

Abstract

Hamartoma is a developmental disorder of various body parts and organs. It is characterized by a nonneoplastic growth of tissue with an uneven distribution and proportion of individual cells. Lesions progress for several years, but usually do not give clinical symptoms, and do not undergo malignant transformation. They occur alone or coexist with other defects, sometimes forming a characteristic clinical picture of a syndrome of congenital defects. Mutations in genes, such as PTEN, GLI3, SDH B/D, PIK3CA and ACT1, cause a dysfunction of the tumor suppressor gene and result in an increased neoplastic transformation. Hamartoma is a lesion between developmental disorders and benign tumors, which occurs frequently in humans, but is very rare in domestic animals. In a histopathological examination, however, it is diagnosed relatively often. In the veterinary literature, both hamartoma and choristoma are attributed mostly to errors in embryogenesis and are not considered as preneoplastic lesions.