Most of the 13 PriC were histotypes usually related to endometriosis (ERH) (n = 10, 77%), including 8 (62%) clear cell carcinomas (CCC) [6,7,8,9,10,11,15,18] and 1 (8%) endometrioid carcinoma (EC) [13]; the remaining case was diagnosed as a serous papillary cystadenocarcinoma but in our opinion, it was likely a CCC or an EC as it was associated with endometriotic foci (unlike serous carcinoma) and the reported immunophenotype did not exclude a CCC/EC (CD10, calretinin, Ki-67) (Table 1) [12]. This evidence concerns the gene MKI67 and endometriosis.