Hamartoma refers to a malformation of the tissues of an organ taking the appearance of a tumor. While the majority of cases are mild, the harmatom can cause discomfort, disrupt organ function, or become cancerous. Surgical intervention may then become essential.

Definition of hamartome

The hamartoma was defined a few years ago as “a nodular formation, single or multiple, comprising the same histological constituents as the normal parenchyma, but in which these constituents are arranged in a less orderly manner and are found in very variable proportions” . In other words, a hamartoma can be defined as a malformation of the tissues of an organ taking the appearance of a tumor (clusters of cells). It is distinguished by the fact that it is made up of the normal cells of a tissue. These proliferate and lead to the development of a cluster of cells: the hamartoma.

Types of hamartomas

Hamartoma is a generic term because it can be used to refer to tissue malformations in many areas of the body. We distinguish in particular:

• mammary hamartoma, or breast hamartoma;
• hypothalamic hamartoma, which affects a specific region of the brain;
• pulmonary hamartoma, which is considered the most common benign lung tumor;
• cutaneous hamartoma, which can appear on the skin in different forms (sebaceous hamartoma, anemic hamartoma or even epidermal hamartoma);
• hamartomas affecting the eyeball such as iris hamartoma or combined hamartoma of the pigment epithelium and the retina.

Hamartomas can be single or multiple. For example, Cowden’s syndrome is characterized by hamartomas in the skin, chest, thyroid, gastrointestinal tract, endometrium, and brain.

Causes of hamartoma

Hamartoma is the result of an overgrowth of normal tissue grouped together in areas where it is not usually found. The origin of this proliferation is still poorly understood. It seems that hamartomas mainly occur during embryogenesis (the development process of the human embryo). As such, hamartoma is sometimes referred to as dysembryoplasia (malformation of a tissue or organ during the embryonic stage).

Evolution of hamartoma

The majority of hamartomas are benign. However, some can progress to a malignant (cancerous) form. Skin hamartomas, for example, can progress to carcinoma (skin cancer). Multiple hamartomas have a higher risk of developing malignancy.

Diagnosis of hamartoma

Hamartomas can develop in many areas of the body. They do not all have the same clinical manifestations. In fact, the examinations allowing their diagnosis may be different depending on the case.

The diagnosis of a hamartoma can for example be based on a physical examination, a medical imaging examination or a biopsy (sample of tissue for analysis).

Harmartomas can appear very differently depending on their location. Some may remain symptomatic (without obvious signs) while others may cause discomfort and / or disrupt organ function.

For example, swelling may be seen in breast hematoma. The hypothalamic hamartoma can cause epileptic seizures, behavioral disorders or even precocious puberty.

The management of hamartoma depends on its location, the associated clinical signs, the risk of complications as well as the condition of the person concerned. Simple medical supervision is set up if the hamartoma is not associated with any discomfort or complication. On the other hand, if disorders or a risk of cancerous evolution are observed, a surgical intervention is necessary. It consists of removing all of the hamartome.

As the origin of hamartomas is still poorly understood, no preventive measures have been identified. On the other hand, the risk of complications can be limited by early detection, regular medical monitoring and appropriate management.