Blog

Many people often notice a small lump under their skin – a “lump” that wasn’t there before – and wonder “what could this be?” Some will ignore it, thinking it’s something insignificant. For others, however, the appearance of a soft tissue mass can cause concern and fear. But what exactly is this mass? Is it a simple lipoma or is it something more serious, like a sarcoma, and how can we tell the two apart?

What is a lipoma?

A lipoma is a common benign tumor that arises from the overgrowth of fatty tissue. It is usually located under the skin (subcutaneously), while, although it can appear anywhere on the body, it appears mainly on the upper and lower extremities (shoulders, arms, thighs) as well as on the neck and trunk.

The etiology of lipoma is not completely known. Possible etiological factors are trauma and metabolic or endocrine disorders, while there is evidence of a genetic predisposition, such as in hereditary syndromes, e.g. multiple familial lipomatosis, where multiple lipomas appear throughout the body.

Lipoma is clinically characterized by the following: It is soft and elastic to the touch, mobile under the skin and basically painless, while it shows slow growth and varies in size.

What is sarcoma?

Sarcoma is a malignant tumor of the soft tissues of the body. It develops in anatomical structures of connective tissue, in the so-called supporting tissues of the human body such as fat, muscles, vessels, nerves, tendons or bones. These tumors can develop anywhere in the body, which differentiates them from cancers that originate from epithelial cells (carcinoma) and develop in specific organs.

Although there are over 100 different types of sarcomas, liposarcoma is the most common type of sarcoma and is related to adipose tissue. It can appear anywhere in the body but – similar to lipoma – it is most often found in the arms and legs, as well as in the trunk of the body (chest, abdomen, retroperitoneum).

The clinical features of a tumor that raise the suspicion of sarcoma and differentiate it from a lipoma are the following: It is usually hard and solid, immobile and adherent, is usually located at a greater depth, while it grows in size faster than a lipoma and may cause pain or neurological symptoms due to pressure on adjacent structures. In these cases, medical evaluation is necessary.

Can a lipoma turn into a sarcoma?

It is extremely rare for a lipoma to turn into a sarcoma (e.g. liposarcoma). Liposarcoma is an independent tumor, with a different biological behavior and genetic background. As a rule, it develops from the beginning as a malignant tumor, and not from a pre-existing lipoma. However, the possibility of a lipoma transforming into a liposarcoma cannot be ruled out, especially in cases of lipomas with large size, rapid growth and the presence of calcifications, intense vascularization, or infiltration into surrounding tissues.

How is the diagnosis made and when is a biopsy required?

The diagnostic approach includes clinical examination and imaging of the mass with ultrasound and mainly with magnetic resonance imaging, which provides more accurate imaging of the tissues (distinguishing between fatty and solid tumors).

• In case the mass
• Is > 5 cm in size
• It is located deep (e.g. intramuscularly)
• It grows rapidly
• It is painful or immobile
• It has suspicious findings on MRI (I will not mention them),

then a biopsy is recommended, i.e. taking a tissue sample for histological analysis, which is the only safe way to completely separate a lipoma from a sarcoma. The technique usually used is a core needle biopsy and is performed by a specialized surgical oncologist or interventional radiologist.

What is the treatment?

In the case of a lipoma, if it does not cause discomfort or an aesthetic problem, surgical removal is not necessary. However, when there is pain, an increase in size or an aesthetic problem, surgical removal is indicated.

However, once a diagnosis of sarcoma has been made, a multidisciplinary and individualized approach is required, based on the characteristics of the tumor and the patient. Surgical removal of the tumor is the cornerstone of treatment for patients with sarcoma, which is often accompanied by other forms of treatment such as radiotherapy, chemotherapy and/or immunotherapy.

Conclusions

The detection of a mass or mass in the body does not automatically mean the presence of malignancy. However, if there are unusual or suspicious features, characteristically, it is necessary to consult a specialized surgical oncologist in order to diagnose or rule out the disease. Early and correct diagnosis is crucial, especially when it comes to rare and serious diseases, such as sarcomas, the treatment of which requires a responsible interdisciplinary and personalized therapeutic strategy.