hamartomatous

Hamartomatous refers to tissue or lesions composed of an overgrowth of mature cells that are native to the affected organ, arranged in a disorganized or haphazard architecture. These lesions are called hamartomas and are generally benign, representing developmental malformations rather than true neoplasms. Unlike choristomas, which are normal tissues in an abnormal location, hamartomas occur in their native site but with altered organization. They typically grow slowly and do not metastasize, though they may cause symptoms through mass effect, bleeding, or obstruction depending on size and location.

Hamartomatous lesions appear in multiple organ systems. In the gastrointestinal tract, hamartomatous polyps are characteristic of several syndromes, including Peutz-Jeghers syndrome, which also features mucocutaneous pigmented macules and is associated with mutations in STK11 (LKB1). Juvenile polyposis syndrome involves SMAD4 or BMPR1A mutations and features multiple hamartomatous polyps. PTEN hamartoma tumor syndromes, such as Cowden and Bannayan-Riley-Ruvalcaba, likewise involve widespread hamartomas and an elevated cancer risk. Hamartomas also occur in the lungs as pulmonary chondromatous hamartomas, and in the skin and other tissues.

Management is generally conservative unless hamartomas cause symptoms or occur as part of a hereditary syndrome with cancer risk, in which case surveillance and targeted treatment, such as polypectomy or surgical removal of obstructive lesions, may be indicated.