hamartoma

noun

ham·​ar·​to·​ma ˌham-ˌar-ˈtō-mə 

plural hamartomas also hamartomata -mət-ə 

: a mass resembling a tumor that represents anomalous development of tissue natural to a part or organ rather than a true tumor

hamartomatous

-ˈtäm-ət-əs  -ˈtōm- 

adjective