Today, there is an increased use of non-medical, invasive cosmetic treatments globally without sufficient awareness of possible health risks. A particular problem is young men injecting large amounts of paraffin oil into skeletal muscles especially on upper arms and chest to increase the visible size of the muscles. Several case reports have suggested that intramuscular injection of paraffin oil induces foreign body reaction and granuloma formation and subsequently hypercalcemia. Our hypothesis is that increased generation of activated vitamin D (1,25(OH)2D3) in the marcrophages may be responsible for the persistent hypercalcemia. Now trhe investigators want to include a large group of men who injected 100-10.000 ml paraffin oil to identify risk factors for developing hypercalcemia and try to understand the pathogenesis of the disease. Additionally, granuloma tissue from selected patients will be cultured ex vivo to investigate whether they produce 1,25(OH)2D3 or PTHrP and to test which drugs can most effectively be used to lower calcium levels in these men. Subsequently, we will try to stratify the men according to the severity of the changes in calcium homeostasis as we suggest that this stratification will be the basis for future intervention trials