Mature ovarian cystic teratoma with disseminated nodular lesions in the pleural and peritoneal cavities: A case report

Mature ovarian cystic teratoma (MOCT) is the most common benign neoplasm of the ovary and has a wide spectrum of radiological presentations. Our aim was to present the radiological characteristics and pathologic findings of a patient with an atypical manifestation of this common disease. A 52-year-old Japanese woman was admitted to our hospital with a large cystic mass in the pelvis and an elevated squamous cell carcinoma antigen level. Computed tomography revealed disseminated cystic lesions in the intraperitoneal and intrathoracic spaces. The lesions contained fat and featured calcifications. Laparotomy revealed many white, spherical nodules in the peritoneal cavity. The results of pathologic examination led to a presumed diagnosis of a foreign body reaction to the contents of an MOCT that leaked into the peritoneal cavity. The patient has been followed up for 13 months and remains free of symptoms without additional treatment. We describe a rare presentation of MOCT, in which we initially strongly suspected an advanced malignancy based on the results of imaging. To make an accurate diagnosis, it is necessary to understand the rare findings associated with MOCT, as well as the common signs on different imaging modalities.