Hamartomas occur in many different parts of the body and are most often asymptomatic incidentalomas (undetected until they are found incidentally on an imaging study obtained for another reason).

Lesions such as adenomas, developmental cysts, hemangiomas, lymphangiomas and rhabdomyomas within the kidneys, lungs or pancreas are interpreted by some experts as hamartomas while others consider them true neoplasms.

Moreover, even though hamartomas show a benign histology, there is a risk of some rare but life-threatening complications such as those found in neurofibromatosis type I and tuberous sclerosis.

[10] Hamartomas are caused by abnormal formation in normal tissue and can occur spontaneously or as a result of an underlying disorder.

[13] Patients may experience hemoptysis, obstructive pneumonia, dyspnea, persistent cough, and chest pain, depending on the size and location.

[14] Typically, lung hamartomas appear as solitary nodules on thoracic computed tomography (CT) scans, with a diameter of less than 4 cm.

They are frequently abundant in blood vessels and contain varying amounts of fat and smooth muscle components.

[23] A hamartoma has been identified as a cause of partial outflow obstruction in the abomasum (true gastric stomach) of a dairy goat.

[25] Cowden syndrome is an uncommon hereditary disorder marked by numerous hamartomas in a range of tissues from all three layers of the embryo.

It is inherited autosomally dominantly, with a germ-line mutation of the PTEN tumor suppressor gene present in about 80% of patients.