PURPOSE: A retrospective study was set up to investigate active pathologic processes associated with sarcoidosis diagnosed in 32 patients. METHODS: Eighteen patients had two identified granulomatous localizations (56%) and 14 patients had three localizations or more (27%). Comorbidity was noticed in nine patients (28% of cases). Sarcoidosis was associated with an infectious disease five times (hepatitis C virus [HCV] infection three times, including one case after recombinant interferon alpha therapy, and HIV and HCV co-infection two times). The association of sarcoidosis with a chronic immunologic inflammatory disease was noticed four times (lupus erythematosus two times, myasthenia and primary biliary cirrhosis). Finally, in two cases sarcoidosis was associated with a neoplasia (non-Hodgkin's lymphoma in a co-infected HIV-HCV patient, ovarian cystadenocarcinoma in another patient). Sarcoidosis preceded or revealed the comorbidity four times.