title: Clear cell carcinoma arising from a uterus-like mass.
abstract: A uterus-like mass is an extrauterine mass with a cavity lined by endometrial tissue and a smooth muscle layer resembling the uterine corpus. It is a rare condition of unknown histogenesis. Herein, we describe a case of clear cell carcinoma arising from a uterus-like mass located in the retroperitoneal space. The patient, a 67-year old nulliparous woman, had been followed with the diagnosis of an ovarian endometriotic cyst for 14 years until ultrasonography and magnetic resonance imaging (MRI) demonstrated an enlargement of the cystic mass with a thickened irregular wall. Suspicion of malignant transformation prompted us to excise the lesion. At laparotomy, the uterus and right ovary appeared normal, and a mass measuring 8 cm was identified in the retroperitoneal space without any connection to the uterus. Grossly, the removed mass was composed of a cyst filled with blackish-brownish fluid and a thick wall resembling uterine myometrium. Microscopically, endometrial tissue inside the cyst, which was diffusely lined by clear cell carcinoma, was identified. Although the histogenesis of a uterus-like mass remains unclear, this case indicates that malignant tumors may occur from a uterus-like mass through the pathway similar to the carcinogenesis of endometriosis-related ovarian neoplasms.
authors.affiliation: Department of Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Baku
authors.initials: B
authors.lastname: Nakakita
authors.forename: Kaoru
authors.initials: K
authors.lastname: Abiko
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Mikami
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Baba
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Ken
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Noriomi
authors.initials: N
authors.lastname: Matsumura
authors.forename: Ikuo
authors.initials: I
authors.lastname: Konishi
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000175:diagnosis / Q000473:pathology*; D000368:Aged; D003560:Cysts / Q000473:pathology*; D004715:Endometriosis / Q000473:pathology*; D005260:Female; D006801:Humans; D009130:Muscle, Smooth / Q000473:pathology; D010053:Ovary / Q000473:pathology; D014594:Uterine Neoplasms / Q000473:pathology*
keywords: adenocarcinoma; clear cell; endometriosis; magnetic resonance imaging; retroperitoneal space