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Corpus callosum lipoma is a rare congenital brain condition that may or may not present with symptoms. This occurs in the corpus callosum, also known as the calossal commissure, which is a wide, flat bundle of neural fibers beneath the cortex in the human brain. Hibernomas are lipomas of brown fat. Intradermal spindle cell lipomas are distinct in that they most commonly affect women and have a wide distribution, occurring with relatively equal frequency on the head and neck, trunk, and upper and lower extremities. : 625 
A fibrolipoma is a lipoma with focal areas of large amounts of fibrous tissue. A sclerotic lipoma is a predominantly fibrous lesion with focal areas of fat.Neural fibrolipomas are overgrowths of fibro-fatty tissue along a nerve trunk, which often leads to nerve compression. : 625 Pleomorphic lipomas, like spindle-cell lipomas, occur for the most part on the backs and necks of elderly men and are characterized by floret giant cells with overlapping nuclei. : 625 
Spindle-cell lipomas are asymptomatic, slow-growing, subcutaneous tumors that have a predilection for the posterior back, neck, and shoulders of older men. : 625 
Superficial subcutaneous lipomas, the most common type of lipoma, lie just below the surface of the skin. Most occur on the trunk, thigh, and forearm, although they may be found anywhere in the body where fat is located. Causes
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. Other conditions
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.Benign symmetric lipomatosis (Madelung disease) is another condition involving lipomatosis. It nearly always appears in middle-aged males after many years of alcoholism, but nonalcoholic males and females can also be affected. Diagnosis
A physical exam is typically the easiest way to diagnose it. Rarely, a tissue biopsy or imaging may be required. The imaging modality of choice is magnetic resonance imaging (MRI) because it has superior sensitivity of distinguishing it from liposarcoma as well as mapping the surrounding anatomy. Treatment
Usually, treatment of lipomas is not necessary, unless they become painful or restrict movement.