Background
Dercum disease (adiposis dolorosa; also known as Anders disease or syndrome, morbus Dercum, adipose tissue rheumatism, adiposalgia, or lipomatosis dolorosa) is an unusual progressive syndrome of unknown etiology characterized by multiple painful lipomas (see the image below) that usually arise in adult life, most often affecting obese postmenopausal women. [1] It is a subcutaneous adipose tissue disease that involves the adipose tissue and its fascia (ie, an adipofascial disorder). Adipofascial disorders represent variations in the spectrum of obesity.
Multiple painful lipomas. Image from Waikato District Health Board and DermNet New Zealand (https://www.dermnetnz.org/assets/Uploads/dermal-infiltrative/w/dercum-1.jpg).
The onset of Dercum disease is insidious, but it has been described in at least one case as having occurred after puerperal weight gain. [2] The pain is out of proportion to the physical findings and is often described by patients as "painful fat.” The pain increases with increases in fatty tissue and in connection with menstruation. Estrogen replacement at menopause has not been shown to reduce the pain.
Since its original description by Francis Xavier Dercum in 1892, the clinical spectrum of Dercum disease has changed to include other components to varying degrees. [3] This is in addition to the painful nodular fatty deposits (which are often unaffected by weight loss). General obesity, easy fatigability and weakness (asthenia), and a wide variety of unexplained emotional disturbances (eg, depression,
Pathophysiology
The pathogenesis and mechanism of Dercum disease remain unknown. The origin of the pain is obscure, and the disease is better known as a clinical entity than as a physiologic or metabolic process. Fatty deposits are thought to cause nerve compression and result in weakness and pain.
A review of the histopathologic findings of Dercum disease showed no consistent histologic abnormality in the adipose tissue that might distinguish these tumors from common sporadic lipomas. [8] In theory, the sudden appearance of the disease together with the incidence of a slight increase in the number of inflammatory cells in the fat could point toward the disease being, in part, an immune defense reaction. Some authors have suggested that the sympathetic nervous system may play a role in the origin and development of the pain.
The report of a case of Dercum disease developing in association with the use of high-dose corticosteroids and then resolving when the dose was reduced suggested a causal relationship, in which alterations of fat metabolism induced by corticosteroid excess might play a role in the development of the syndrome. [9] An earlier study suggested that a defect in the synthesis of monounsaturated fatty acids might play a role in its development. [10] Further studies are needed to support this hypothesis and to identify a specific biochemical defect.
It has been suggested that Dercum disease may be an expression of familial multiple lipomas, an autosomal dominant disease characterized by multiple lipomas that are usually asymptomatic. This suggestion was based on study of the family patterns of two siblings with Dercum disease, which suggested that the disease segregates in an autosomal dominant fashion with variable phenotypic expressivity, ranging from totally asymptomatic to extremely painful lipomas. [11] However, most cases of the disease are found to be sporadic, with no specific genetic mutations.
Mutational analysis excluded the 8344A→G mitochondrial mutation seen in other patients with multiple lipomas. [8, 11] The A→G transition at position 8344 in the tRNAlys gene of mitochondrial DNA has been described in the MERRF (myoclonic epilepsy and ragged-red fibers) syndrome. A number of reports have described the presence of multiple lipomas resembling those of multiple symmetric lipomatosis in some members of pedigrees with MERRF harboring the 8344 tRNA mutation. [12]
Gamez et al described an unusual syndrome characterized by maternally inherited multiple symmetric lipomatosis in a pedigree harboring the 8344 mutation in the tRNAlys gene of mitochondrial DNA. [11] Although the probands in this study harbored this mutation and had sensory polyneuropathy, they lacked the typical neuromuscular manifestations of the MERRF syndrome.
In 2015, an abnormal lymphatic phenotype was discovered in three patients with the disease compared with four female controls by using near-infrared fluorescence (NIRF) lymphatic imaging. [13] The lymphatic vessels in the three participants with Dercum disease were intact and dilated but could not readily clear lymph when compared with the lymphatics in the four control subjects. Further NIRF imaging revealed masses of fluorescent tissue within the painful nodules, suggesting a lymphovascular etiology.
Etiology
The cause of this poorly understood disorder is unknown, though multiple candidate theories have been proposed, including nervous system dysfunction, lymphovascular disorder, adipose tissue dysfunction, endocrine dysfunction, mechanical pressure, trauma, and inflammation, among others. None of the etiologic theories has been consistently substantiated.
High-dose corticosteroids were the suspected cause in a reported case. [9] Another case report documented traumatic injury sustained from a motorcycle accident approximately 5 years previously as the cause of Dercum disease. [14] In two patients with rheumatoid arthritis treated with tocilizumab, an atypical juxta-articular form of Dercum disease developed; discontinuance of tocilizumab was followed by progressive disappearance of the pain associated with the fatty masses. [15]
Epidemiology
Dercum disease is thought to be rare, though its prevalence has not been established.
The disease is most commonly seen in persons aged 45-60 years; it may occur in women younger than 45 years. A survey of patients with the disease concluded that 85% of patients developed symptoms before the onset of menopause. [3] Dercum disease is exceedingly rare in children; however, there have been reports of pediatric cases, including one involving a prepubescent 8-year-old girl. [16]
Dercum disease is 20 times more common in females who are postmenopausal, obese, or overweight than in other people. It can occur in individuals who are not obese. Of those affected by the disease, 16% are males.
Prognosis
The course of Dercum disease is a chronic one. Over time, the disease may progress and become more debilitating.
Patient Education
Educating patients about the chronicity of Dercum disease and the limited treatment modalities available is important. Appropriate information about the aggravating and relieving factors should be provided.
It is also important to address any possible needs that persons with disabilities may have, preferably with the assistance of an occupational therapist and a social worker. Various aids may be required in the home and at work.
There are several social networking support groups related to Dercum disease. [17] The Dercum Society website, featuring information on Dercum disease for patients, was created in 2005 by a patient with the disease. Other organizations supporting patients with this disease include the American Chronic Pain Association and the Fat Disorders Resource Society.
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Multiple painful lipomas. Image from Waikato District Health Board and DermNet New Zealand (https://www.dermnetnz.org/assets/Uploads/dermal-infiltrative/w/dercum-1.jpg).
