A 32-year-old, previously healthy woman with a diffuse, complex tumoral process is described. While she was being evaluated for primary infertility, a laparoscopic procedure revealed a disseminated peritoneal process associated with bilateral ovarian lesions. A clinical diagnosis of stage III ovarian cancer was made and total hysterectomy, bilateral salpingo-oophorectomy, and omentectomy were performed. Pathologic studies showed an admixture of leiomyomatosis peritonealis disseminata (LPD) endometriosis, and an extensive multicystic mesothelial proliferation. Although endometriosis is known to occur in conjunction with either LPD or multicystic mesothelioma, to our knowledge this is the first report of all three lesions occurring simultaneously.