Lipoma is a common superficial benign tumor composed of mature fat cells. It is more common and is most often seen in middle-aged adults (50 to 60 years of age). It can occur anywhere and presents as single and multiple subcutaneous confined masses, and is also seen as part of the Gardner syndrome presentation. Cytogenetic studies suggest an association with chromosomal alterations. The masses grow slowly and rarely become malignant. Surgical treatment is required for larger sizes. The etiology is unknown, but a few patients have a family history or are born with it. 1. Symptoms and signs: Single or multiple subcutaneous limited masses, or coexisting with hemangioblastoma, usually no conscious symptoms except for large tumor affecting local movement or pain caused by compression of nerve. It is rarely malignant. (1) It can occur in any location: lesions are usually found in the neck, shoulder, back and abdomen, but also in the retroperitoneum and viscera. They are most commonly found in the subcutaneous tissue of the head, neck, arms and chest. Approximately 7% of lesions are multiple, with multiple lesions developing early and single lesions developing late and stopping growth at a certain point. (2) Solitary lipoma: Lipomas are variable in shape, often appearing as soft subcutaneous masses that are oblate, nodular, lobulated or tip-shaped, or sometimes diffuse masses that can be pushed. They are soft and elastic and do not adhere to the surface skin. They are generally well-defined and slow-growing, unless they are too large and produce painful sensations due to compression of local nerve branches, and are generally asymptomatic, with large ones reaching several kilograms. After the volume of the swelling reaches a certain size, it often stops growing and becomes quiescent. The skin on the covered surface is normal, and most lesions are <5 cm in diameter, with a wide base. When the base of the tumor is squeezed, the surface skin may appear "orange peel" like, which is caused by the pulling of the fiber bundles in the subcutaneous fat going vertically towards the skin. Sometimes spontaneous atrophy or calcification and liquefaction may occur. (3) Multiple lipomas: They can be scattered all over the body or confined to a certain part of the body surface, with the number of more than two or even hundreds. They appear as painless subcutaneous nodules of different sizes, and some of them grow symmetrically. They are painful when actively growing. It is often associated with neurofibromatosis. (4) Angiomyolipoma: It has all the characteristics of a typical lipoma and is usually seen in young and middle-aged men. Sometimes there is a family history. It is slow in course, usually in the forearm, waist and femur, and is the size of a fava bean or soybean, sometimes expanding and shrinking on its own with pain. The cause of pain is presumed to be related to hemangioblastoma, or due to the stimulation of surrounding tissues such as edema and inflammation or the compression of surrounding tissues by the tumor. (5) Syndrome manifestations: Lipoma can also be seen as part of Gardner's syndrome. This syndrome is characterized by multiple osteomas of the face, multiple polyps of the colon, lipomas, fibromas, fibrosarcomas and smooth muscle tumors. 2.Treatment Smaller lipomas with slow development and no clinical symptoms usually do not need to be treated. If it grows very large, feels painful or affects the beauty, surgery can be considered to remove it. 3.Dietary care Specific dietary recommendations should be made according to the symptoms and consult with the doctor to ensure a reasonable diet, comprehensive and balanced nutrition, and a light diet without spicy and stimulating foods. The etiology of the disease is unknown, but a few patients have a family history or have it since birth. 5.Disease diagnosis Sometimes it is necessary to differentiate from neurofibroma, lymphangioleioma, cavernous hemangioma, dermatofibrosis and cutaneous pig cysticercosis. If necessary, puncture and aspiration examination should be performed. (1) Angiomyolipoma: Proliferation of capillaries and endothelial cells in the tumor tissue, narrowing of the vascular lumen, and fibrinous thrombus in it. (2) Cutaneous porcine cysticercosis The cyst is not lobulated and porcine cysticercosis can be found. 6. Pathogenesis The lesions are located in the deep dermis and subcutaneous layer and have a spherical, nodular or lobulated appearance. The tumor is mainly composed of mature adipocytes with a thin and intact envelope. Fibrous tissue is distributed from the envelope to the tumor body in fibrous intervals, forming trabecular branches that separate the tumor body into lobules of varying size and larger than normal fat lobules, with a light yellow, soft, greasy fat surface. Capillaries enter the tumor with the trabecular branches. The vascular distribution of the tumor is often uneven, with more vessels on the surface or on one side of the tumor. When the fibrous tissue increases to about half of the tumor surface, it is called fibrolipoma. If the vascular component increases to about half of the tumor surface, the tumor is called angiolipoma. Microscopically, capillary endothelial cell proliferation and luminal narrowing, sometimes with thrombosis, can be seen. The size and morphology of the tumor cells, resembling normal adipocytes, are sometimes seen as focal mucinous degeneration. The presence of foam cells, small astrocytes, and spindle cells with stromal mucus-like in the region is called mucinous lipoma. The tumor occasionally shows hemorrhage, necrosis, calcification, liquefaction or yellow tumor-like changes. Genetic studies have shown that this disease is associated with chromosome 12q, 6p and 13q alterations. 7.Examinations Laboratory tests are not described. Complications The vast majority of lipomas do not cause direct symptoms or complications. 9.Prognosis 1% may recur, suggesting incomplete excision or atypical changes. Most of the lesions are <5cm in diameter and generally have no conscious symptoms except for pain caused by large tumors that affect local movement or compression of nerves. Very little malignant change.