Context Dercum’s disease (DD) and Roch-Leri mesosomatic lipomatosis (LMS) are rare and poorly characteri -zed diseases. The clinical presentation combines multiple lipomas, painful in DD in contrast with LMS, without lipoatrophy. ObjectiveTo identify any specific metabolic and immune phenotype of DD and LMS with the aim to improve their treatment.Design & PatientsThis monocentric retrospective study included 38 patients: 9 DD, 11 LMS and 18 healthy controls. Metabolic and immunohematological characteristics of each group were compared.Results The median age of the patients was similar in the 3 groups (31 years). The number of women, and of basophils, and CD3+, CD4+ and CD8 + T lymphocytes was significantly higher in the DD versus the LMS group, without any difference of the metabolic parameters. Weight, BMI, blood pressure, gamma-GT, leptin, fasting insulin and C-peptide levels, fat mass percentage, and intra/total abdominal fat ratio were significantly higher in each lipomatosis group compared with the control group. Compared with the control group, the DD group had significantly higher fasting blood glucose, LDL-cholesterol, platelets, leukocytes, basophils, and a lower NK cell count, whereas the LMS group had a significantly lower rate of CD3, CD4, and CD8 lymphocytes.ConclusionDD and LMS show a common background of obesity and metabolic phenotype, but a distinct immunohematological profile characterized by a higher number of platelets, leukocytes and basophils in DD patients, an inflammatory profile that could contribute to pain. T lymphocyte depletion was present in LMS. These findings could offer specific therapeutic opportunities, especially for painful DD.NCT0178428