Lipoma

A lipoma is a benign tumor made of fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than 5 cm in size. Common locations include upper back, shoulders, and abdomen. A few people have a number of lipomas.X-ray of a lipomaMedical ultrasonography of a lipoma in the thenar eminence: It is hyperechoic compared to adjacent muscle, and relatively well-defined, with miniature hyperechoic lines.T1 MRI of the same lipoma: High intensity signal mass with regions of ill-defined margins.Ultrasonography of a liposarcoma for comparison: In this case a heterogeneous mass consisting of an upper hyperechoic portion, corresponding to lipomatous matrix, and areas of hypoechogenicity corresponding to nonlipomatous components.Ultrasonography of a liposarcoma mimicking lipoma. A homogeneous hypoechoic mass presenting with the same appearance of lipoma. It was clinically distinguished by having rapid growth.MRI showing lipoma of the armX-ray showing lipomaIntraoperative photo.Operating field after removal of the lipoma: Arrow marks the median nerve that was compressed by the lipoma.The resected lipoma(8 cm × 6 cm × 3 cm)Lipoma removed from human torsoLipoma removed from the breastThis lipoma was removed from the thigh of a 39-year-old male patient. It measured about 10 cm in diameter at the time of removal. A lipoma is a benign tumor made of fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than 5 cm in size. Common locations include upper back, shoulders, and abdomen. A few people have a number of lipomas. The cause is generally unclear. Risk factors include family history, obesity, and lack of exercise. Diagnosis is typically based on a physical exam. Occasionally medical imaging or tissue biopsy is used to confirm the diagnosis. Treatment is typically by observation or surgical removal. Rarely, the condition may recur following removal, but this can generally be managed with repeat surgery. They are not generally associated with a future risk of cancer. About 2% of people are affected. Lipomas typically occur in adults between 40 and 60 years of age. Males are more often affected than females. They are the most common noncancerous soft-tissue tumor. The first use of the term 'lipoma' to describe these tumors was in 1709. The many subtypes of lipomas include::624–5 The tendency to develop a lipoma is not necessarily hereditary, although hereditary conditions such as familial multiple lipomatosis might include lipoma development. Genetic studies in mice have shown a correlation between the HMG I-C gene (previously identified as a gene related to obesity) and lipoma development. These studies support prior epidemiologic data in humans showing a correlation between HMG I-C and mesenchymal tumors. Cases have been reported where minor injuries are alleged to have triggered the growth of a lipoma, called a 'post-traumatic lipoma'. However, the link between trauma and the development of lipomas is controversial. Lipomatosis is believed to be a hereditary condition in which multiple lipomas are present on the body. Adiposis dolorosa (Dercum disease) is a rare condition involving multiple painful lipomas, swelling, and fatigue. Early studies mentioned prevalence in obese postmenopausal women. However, current literature demonstrates that Dercum disease is present in more women than men of all body types; the average age for diagnosis is 35 years.