To the Editor: We read with interest a recent article by Cheung and Cheung [1] reporting a case diagnosed as cystic endosalpingiosis and adenomyosis, having encountered a similar case recently (Fig). In another article, Sizzi et al [2] reported similarlooking cystic lesions in the pelvis, but these lesions were diagnosed as benign cystic peritoneal mesothelioma. There are case reports in the literature supporting either of these diagnoses for similar cystic lesions. Given this inconsistency, reports in the literature could be very confusing to clinicians in making a clinical diagnosis based on similar operative findings. We support the diagnosis of cystic endosalpingiosis for these pelvic cystic lesions instead of mesothelioma in our case. This is because the histological features in our case showed flat to cuboidal cells with no atypia or mitoses lining the wall of these cystic lesions, and there were no mesothelial lining in the cysts to support the suggestion of mesothelioma. Moreover, a recent immunohistochemical study reported by Esselen et al [3] showed that these pelvic cystic lesions have tubal antigens similar to the tubal epithelium. Therefore, we believe that they could be of the same tubal origin. Apparently, the histology of these cystic lesions may not be sufficiently discrete to distinguish