CT Features and Its Pathologic Fundaments in External Endometriosis

Objective To discuss the relationship of CT findings and histopathology in the patients with external endometriosis (EEM), and to evaluate the value of CT in diagnosis of EEM.Materials and Methods The data of clinical, CT and histopathology in 24 patients with EEM were reviewed retrospectively. All cases were examed before and after enhancement.Results 51 lesions were found in 24 cases with EEM, which included solid type in 3, mixed cystic and solid type in 4 and cystic type in 44. The solid type was shown as soft tissue mass which was composed of fibrous tissue, little endometrial tissue, hemosiderin and a few lymphocytes and plasma cells. For cystic lesions, the wall was composed of two layers, outer was fibrous capsules and inner layer contained endometrial tissue; the cystic walls appeared as rough, thicken adhering with adjacent tissues or organs.. The cystic fluid was composed of mixed blood from varying periodic ectopic endometrial tissue hemorrhage. On CT, it was appeared as hyperdensity, hypodensity or mixed. In the patients with mixed cystic and solid lesions, the findings of CT and histopathology appeared as those of two types.Conclusion Findings of CT in the cystic type and mixed type of EEM were specific. The solid type was lacked of specific findings, however its diagnosis could be made if the findings of CT was linked to the related clinical symptom in menstrual period.