A<unk>  is a common, benign tumor composed of fatty tissue. In 1914, Dr. Gery and colleagues first described Hibernoma, tumor of brown fat tissue.<unk>  may be classified into different subtypes depending on the classification system. They may be classified according to the anatomical location, the related tissues or other characteristics.<unk>  is formed from mature adipocytes and is histologically indistinguishable from fat tissue. Recent studies have observed cytogenetic abnormalities in 50-60% of<unk> s, suggesting its role in the<unk>  pathogenesis. Rearrangements of chromosome 12 are the most commonly cytogenetic abnormality. In a cross-sectional appearance, the<unk>  is pale yellow to orange color and has a uniform greasy surface with a lobular pattern. The subcutaneous<unk>  is usually encapsulated and has a distinct lobulated pattern. There is no established cause for<unk> . However, trauma and some genetic abnormalities have been associated with its development.<unk>  must be differentiated from<unk> rcoma, normal adipose tissue, adrenal myelolipoma, angiomyolipoma, and other<unk> tous tumors.<unk>  incidence is 100 per 100,000 individuals worldwide annually.<unk> s tend to affect middle age individuals. It affects men at a greater extent than women. Common risk factors in the development of<unk>  are trauma and genetic factors.<unk>  affects trunk, shoulder, upper arm, and neck at a greater extent. These tumors are completely benign and recurrence is one of their complications.<unk>  can be diagnosed clinically. However, a combination of clinical features and imaging studies are usually used for their diagnosis. Biopsy may be indicated in case of rapidly enlarging mass or unusual findings such as firm consistency. The most common symptom of<unk>  is an asymptomatic slowly growing mass with a soft consistency. However, the deep<unk>  may be symptomatic depending on their site and size. Symptoms include pain, restriction of movement in large<unk> , feeling of fullness or discomfort, and  palpitation and dyspnea in mediastinal<unk> s. Physical examination of patients with a<unk>  is usually remarkable for a mobile, painless mass with a soft consistency. This mass often occurs in the neck, shoulders, back, arms and thighs. Sometimes,<unk>  may cause limitation in the range of motions of the extremities depending on their size and locations. Neuromuscular examination of patients with<unk>  may be remarkable for positive Tinel's sign and Phalen's sign. Lasègue's sign may be positive in case of lumbosacral<unk> . On CT, the<unk>  is seen as a well-delineated mass with absorption density characteristic of fatty tissue. Findings on an MRI suggestive of<unk>  include a well-defined lesion with intensity similar to that of subcutaneous fat. Ultrasound may be helpful in the diagnosis of<unk> . Findings on an ultrasound suggestive of<unk>  include Hypoechoic, minimally heterogeneous lesion. Treatment options of<unk>  include simple excision, liposuction, and deoxycholate injection.
Lipoma
Condyloma
Mammary adenosis
Liposarcoma
Angiokeratoma
Xanthoma
Nevus
Chondroma