Male-to-female transgender (MtF TG) individuals often report using illegal subcutaneous silicone injections for body feminisation. It leads to silicone dissemination and various dermatologic complications.We report the long-term complications of these feminisation procedures with blood smear examination and dermatologic examination.Between July 2015 and December 2015, 77 MtF TG consulting at Bichat Hospital (Paris, France) were included in this cross-sectional study. Blood smear examinations were performed by a trained haematologist to quantify the presence of silicone vacuoles in monocytes.All patients reported a history of massive amounts of silicone injections (mean 4 L, range 0.5-15 L). Most patients were South American (75/77, 97%). Fifty-nine (59/75, 79%) were HIV-seropositive, mostly with undetectable HIV RNA plasma levels (46/58, 80%). Clinical examinations reported dermatologic complications for all patients: lymphatic or subcutaneous migration of silicone (59%), inflammation (50%), varicose veins (39%), post-inflammatory pigmentation (20%), infection (14%) and abscesses (4%). Blood smear examination showed intracytoplasmic vacuoles containing silicone in monocytes in all patients.We did not chemically prove the silicone nature of the vacuoles. The design of this study does not allow evaluation of short-term complications that should not be minimized.Illicit massive silicone injections always induced chronic and definitive silicone blood diffusion with dermatologic complications. This study highlights the dangers and the inefficiency of clandestine esthetic surgery. There is a need for targeted information campaigns with transgender populations about silicone injections. Otherwise, these practices may persist.