Mesotherapy is a form of medical therapy popular in Europe and South America. It is used for treating a variety of medical conditions, including the treatment of localized fat deposits and cellulite. Phosphatidylcholine/deoxycholate injections are a popular technique to treat localized fat accumulations and have recently become synonymous with mesotherapy, although their history and technique are distinct. To treat localized fat deposits, phosphatidylcholine (PC) and deoxycholate (DC) are utilized. To date, there have been no published histological studies that explain the mechanism of action of PC and DC.

Method. In this study the authors have obtained skin biopsies from a patient who had undergone mesotherapy with PC and DC. Punch biopsies were taken at one and two weeks after the procedure.

Results. Each of the biopsies taken at one and two weeks after treatment with PC and DC showed a normal epithelium and dermis, with a mixed septal and lobular panniculitis. The fat lobules were infiltrated by increased numbers of lymphocytes and, in particular, macrophages. The macrophages consisted of conventional forms, foam cells, and multinucleated fat-containing giant cells. The inflammation was associated with serous atrophy and microcyst formation.

Conclusion. This study demonstrates that mesotherapy with PC and DC affects the subcutaneous fat. We theorize that the reduction of subcutaneous fat likely follows inflammatory-mediated necrosis and resorption.