Abstract
Peritoneal cystic mesothelioma is a relatively rare neoplasm, characterized by cystic lesions of various sizes on both visceral and parietal peritoneal surfaces. When located in the pelvis, a wide spectrum of cystic or multicystic lesions should be included in the differential diagnosis. From an imaging point of view, no definite differential diagnostic suggestions can be made, because reports of peritoneal cystic mesothelioma are few and consist mostly of case reports. The rarity of this disease, as well as its malignant potential, include it among the challenging differential diagnoses of pelvic/peritoneal cystic masses, especially in the case of a paraovarian cyst with identification of ovaries with non-suspect morphology. In this case, repetition of transvaginal ultrasound examination after a few weeks seems to be appropriate. When the findings persist, cystic peritoneal mesothelioma must be included in the differential diagnosis. Nevertheless, it seems that the definitive diagnosis of peritoneal cystic mesothelioma can be made only after surgery. Imaging with ultrasonography and magnetic resonance could play an important role in disease follow-up.