Multiple symmetric lipomatosis (MSL) is a rare subcutaneous tissue disease characterized by growth of symmetric non-encapsulated masses of adipose tissue mostly around the face and neck with variable clinical repercussions (e.g. reduced neck mobility, compression of respiratory structures).
MSL primarily affects men and has a sex ratio of 15:1 to 30:1, depending on the region.The disorder may occur in all ethnic groups.. Prevalence and incidence are not known but estimates are available for certain countries (e.g. prevalence for males in Italy 1/25,000). More than 300 cases have been reported.
Onset is generally in mid- to late-adulthood (30-60 years of age). The course of MSL is characterized by rapid early development, followed by slow progressive growth of adipose deposits in and around the face, neck, occipital region, supraclavicular fossa, and shoulder areas. The thighs may be affected. Patients often initially present to medical attention for esthetic reasons and/or difficulties when dressing. Over time, neck muscles may become compressed reducing the size of the trachea and esophagus with associated respiratory obstruction and obstructive sleep apnea. Patients also often have polyneuropathy, liver disease, and metabolic syndrome with abnormal glucose tolerance, and hyperlipidemia. Most affected patients are obese but some rare cases (1/10) show a normal body weight. Malignant transformation into liposarcoma (see this term) has been reported in very rare cases.
The pathogenesis of MSL is not fully understood, but recent findings suggest that it may be related to defective noradrenergic regulation of mitochondria in brown fat. The disease is strongly associated with alcohol abuse (up to 90% of patients).
Diagnosis of MSL may be complicated because of confusion with obesity. Clinical findings showing a specific distribution of adipose tissue are diagnostic (specifically, sparing of the distal arms and legs). Alcohol abuse is also suggestive of MSL. Computed tomography (CT) or magnetic resonance imaging (MRI) can be used to confirm the presence of symmetrical, non-encapsulated fat deposits. Biopsy of fatty masses can also be used to rule out liposarcoma.
Obesity and liposarcoma are the main differential diagnoses. Other disorders to consider include Cushing syndrome, familial angiolipomatosis, Prune belly syndrome (see these terms) and lymphoma.
Some cases with autosomal dominant inheritance patterns or suspected mitochondrial inheritance have been described.
In some patients, treatment may not be required. When treatment is needed for esthetic reasons, or due to sleep apnea, aerodigestive tract compression, or severe pain, it generally involves surgery such as lipectomy, liposuction (or ultrasound-assisted liposuction). Cessation of alcohol intake and weight loss may help in halting progression in some cases.
MSL is basically a benign condition but in some cases there may be serious physical, cosmetic and psychological repercussions. Associated disorders may affect the prognosis. Alcoholism plays a greater role in morbidity and mortality than MSL itself.
Last update: November 2014
- Pr Marie-Christine VANTYGHEM