There are many reasons a back lipoma will begin to form, and the most common causes are genetic conditions, injury, and the development of a quick-growing cancer. A lipoma is composed of encapsulated adipocytes, or fat cells. The rounded lump may move under the skin with very little pressure because it is not attached to any surrounding tissue. Lipomas are usually painless unless the slow-growing mass compresses the nerves around it.
Some lipomas are thought to be caused by a traumatic injury to the area of development. A hard blow to the back may result in the formation of a small lipoma. This type of lump is called a posttraumatic lipoma.
A hereditary condition called familial multiple lipomatosis is characterized by the appearance of small fatty lumps under a layer of skin. In addition to the back lipoma, a person with this condition may notice the formation of lipomas on the chest, arms, and legs. Rarely, the lipoma develops on the face or head.
Another condition that may cause a back lipoma is called adiposis dolorosa. The fatty tumors may also form on the chest and the upper portions of the arms and legs. Lipomas can grow very large, causing extreme pain where the tumor presses on adjacent nerves. More women than men are diagnosed with this painful disorder, which includes symptoms of joint and bone pain, headache, and fatigue.
If the lipoma develops primarily on the upper shoulder girdle of the back, the cause of the condition may be a disorder called benign symmetric lipomatosis. It is also called Madelung’s disease or benign symmetric lipomatosis of Launois-Bensaude. More men than women are affected by this condition. Many of the men diagnosed with this disorder have a history of alcohol abuse.
A cancerous form is called a liposarcoma. These very rare tumors form in the adipose cells of soft tissue and can be found anywhere on the body. The development of the liposarcoma may be accompanied by weight loss and abdominal pain. Magnetic resonance imaging (MRI) may be used to differentiate between a benign lipoma and the liposarcoma. A biopsy of the growing mass will indicate if there is a need for further treatment.
Non-cancerous back lipomas may be treated in several ways. The first is to simply leave the benign lump alone. Some people find the lumps unsightly and want them removed for cosmetic reasons. An endoscopic procedure or liposuction can be used to remove the lipoma. It may be injected with a steroid or phosphatidylcholine substance that causes the fatty cells to atrophy in a process called lipolysis.