Benign tumors of adipose tissue are classified as lipoblastomas, constituted by immature fat cells; hibernomas, consisting of mature brown fat cells and lipomas, formed by mature white fat cells.
Lipomas are the most frequent fatty tissue tumors and probably also the most frequent soft tissue neoplasm. They can be observed in any age group, although they are more common in young adults. They occur more frequently in women because of the greater proportion of body adipose tissue they present. These types of benign tumors are diagnosed more frequently in the 5th and 6th decades of life and are rare in the childhood.
Are Lipomas Genetic?
Its etiology is unknown. Various theories have been proposed without any having been fully accepted: sporadic, genetic, endocrine/metabolic and traumatic. Recently, certain genetic mutations have been studied in these tumors, especially at the level of 12q13-15 and 6p13q.
The cause of lipomas is unknown. Lipomas are usually hereditary; therefore, there may be genetic factors involved in their formation.
They are usually solitary tumors, but there are 3 types of multiple lipomatosis syndromes: Dercum’s disease (also known as adiposis dolorosa), multiple familial lipomatosis, and symmetric benign lipomatosis (also called Madelung’s or Buschke’s disease).
Lipomas can be located anywhere in the body. They are usually located in the subcutaneous plane and are asymptomatic (which means they do not generate any symptom); they are rarely located in deep planes: intramuscular, intermuscular, periosteal or intraosseous, being able to produce compression of the adjacent nerves.
The clinical aspect varies depending on the location. In general, they manifest as well-delimited, mobile skin neoformations with a soft (rubbery) and elastic consistency. Its growth is slow until it reaches a stable size (on average, two to 10 centimeters) and, generally, they do not produce symptomatology. Some grow considerably and they are associated with a great variety of symptoms that can affect the patient’s daily activities.
Its usual topography is the trunk and the proximal part of the upper limbs. Localization in hands is rare: it represents only the 5% of benign tumors.
At the hand level, the most common location is in the antebrachial, thenar and hypothenar regions. Those that involve phalanges (fingers) are very rare, with an approximate incidence of 1%. The localization in this area causes a decrease in the function and mobility of the hand and/or wrist, characterized by an image of “trigger finger”, alterations in flexion and pincer function.
Patients may also manifest neurological symptoms by compression in the peripheral nerves of the hand (alterations in sensitivity, pain, carpal tunnel syndrome, etc.).
Regarding the diagnosis of this pathology, the clinical history, and physical examination are sufficient in most cases. In deep lipomas the support of imaging tests is necessary; simple radiography reveals a radiolucent mass, ultrasound helps to detect and identify space-occupying lesions and differentiates a solid mass from a cystic and the MRI (magnetic resonance imaging), apart from the diagnostic orientation, locates exactly the tumor and indicates its relationship with adjacent structures, such as nerves, while also helping the doctors with surgical planning.
The histological study shows that these lesions are constituted by adipose tissue that resembles normal.
When it is completely removed, one can observe a capsule surrounding the aggregate of adipocytes. A group of lipomas is the so-called hibernomas, constituted by lipoblasts. Depending on the associated component, we can talk of angiolipoma, fibrolipoma, angiofibrolipoma or polymorphic lipoma. The differential diagnoses include hibernomas, lipoblastomas, angiolipomas, and neurofibromas.
The treatment of choice is surgical resection. The indications for performing this procedure are the presence of pain and compression of neurocutaneous structures, which occurs more frequently when located in narrow spaces such as the hand. The result after surgery is generally good; however, because extensive dissection must be performed, with the mobilization of neurovascular bundle, loss of function or sensitivity may occur.
A lipoma is not cancer and is usually inoffensive. Rarely, a lipoma becomes a serious condition. However, if you notice a lump or swelling anywhere on the body, have it checked by a doctor.
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