Adnexal masses associated with peritoneal involvement: diagnosis with CT and MRI

Given the unique intra-peritoneal anatomic location of the adnexa, tubo-ovarian diseases can commonly spread into the peritoneal cavity. Peritoneal seeding may occur in a spectrum of adnexal conditions including infectious diseases, endometriosis, and benign or malignant primary or secondary ovarian tumors. CT is usually the imaging modality on which the concomitant involvement of the peritoneum and the ovary is depicted. The first diagnosis to be considered by the radiologist is generally peritoneal carcinomatosis from ovarian cancer but other conditions cited above have also to be borne in mind and may be suggested on the basis of careful assessment of CT findings or on further MR findings. MRI may indeed help characterize the lesions in some cases. The purpose of this review is to describe the clinical and imaging patterns of peritoneal involvement that may be found in association with different ovarian lesions. Familiarity with these patterns and diagnoses will help the radiologist narrow the differential diagnosis and make an accurate diagnosis, thus facilitating patient management and avoiding unnecessary invasive treatment.