Painful obesity disease mainly manifests as painful nodules or fat masses on top of obesity. Painful obesity is a rare autonomic nervous system disorder of unknown etiology, manifesting as an abnormal accumulation of subcutaneous fat in certain areas of the trunk and accompanied by spontaneous pain in that area. The disease was first described by Dercum (1892) and is therefore also known as Dercum’s disease. What can cause obesity with painful nodules or fat mass symptoms? The disease may be associated with a metabolic disorder. It has also been reported to be related to immune dysfunction, but this has not been elucidated. The pathogenesis is unknown. In the past, it was thought to be related to hypothalamic and endocrine disorders, but Pimenta et al. (1992) confirmed that the pituitary, adrenal, thyroid and gonadal secretion functions are normal in patients with this disease, and found that patients have the phenomenon of peripheral insulin resistance, normal uptake and oxidation of sugar, low response to norepinephrine, and lack of insulin anti-lipolytic effect, so it is thought that this disease may be related to metabolic disorders. Local pain may be caused by abnormal fat accumulation affecting the dermal nerves, or hyperalgesia may be caused by degeneration of the dermal nerves. It has also been suggested in the literature that it is related to immune dysfunction, but this has not been elucidated. The majority of female patients with this disease are 30 to 50 years old, i.e. women of childbearing age, and are often associated with premature menopause and early hypogonadism. The main manifestation is the appearance of painful nodules or fat masses on the basis of obesity, varying in size, with fat deposited in the trunk, neck, axilla and waist and buttocks, with asymmetric distribution. The fat nodules are soft in the early stage and hard in the late stage. As the fatty nodules increase in size, the pain increases, along with numbness, weakness and sweating disorders. The nature of the pain is sharp pinprick-like or knife-like pain, paroxysmal or continuous, with pressure pain along the nerve trunk. It is often accompanied by arthralgia, and generalized weakness is the prominent symptom, but there is no evidence of organic pathology.