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Pathology International 2014
doi:10.1111/pin.12218
Case Report
Clear cell carcinoma arising from a uterus-like mass
Baku Nakakita,1 Kaoru Abiko,1 Yoshiki Mikami,2 Aki Kido,3 Tsukasa Baba,1 Yumiko Yoshioka,1 Ken Yamaguchi,1 Noriomi Matsumura1 and Ikuo Konishi1 Departments of 1Gynecology and Obstetrics and 3Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto and 2Department of Diagnostic Pathology, Kumamoto University Hospital, Kumamoto, Japan
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. Key words: adenocarcinoma, clear cell, endometriosis, magnetic resonance imaging, retroperitoneal space
A uterus-like mass is considered a rare form of endometriosis, characterized by central endometriosis with cavity formation and smooth muscle proliferation surrounding the
Correspondence: Kaoru Abiko, MD, PhD, Department of Gynecology and Obstetrics, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Email: [email protected] Disclosure: None declared. Received 23 May 2014. Accepted for publication 6 September 2014. © 2014 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd
cavity.1 A total of 26 cases in English and 4 cases in Japanese scientific literature, including those arising in the ovaries, broad ligaments, or other organs, such as the small bowel or colon, have been reported previously,2–8 and only one study described the occurrence of a malignant tumor.8 Recently, we identified a case of clear cell carcinoma in a uterus-like mass of the retroperitoneal space. The patient had been followed with serial ultrasound and occasional MRI for 14 years until a demonstrated change suggested neoplastic occurrence of a malignant tumor. This case prompts a discussion regarding the diagnostic challenges and histogenesis of this rare entity.
CLINICAL SUMMARY A 53-year-old postmenopausal woman (gravida-1, para-0) presented with low back pain and was noted to have lumbar vertebrae disc herniation and a 5 cm pelvic mass by MRI and then was referred to our clinic. She had a past history of appendectomy and left salpingo-oophorectomy for appendicitis and a left ovarian tumor of unknown histology at 16 years of age and 32 years of age, respectively. On admission, ultrasonography demonstrated a cystic mass measuring 6 cm located on the right side of the pelvis. The cyst wall was smooth and 5-mm thick, and no solid component was identified. Serum CA125 and CA19-9 were 24 U/mL (normal,
Pathology International 2014
doi:10.1111/pin.12218
Case Report
Clear cell carcinoma arising from a uterus-like mass
Baku Nakakita,1 Kaoru Abiko,1 Yoshiki Mikami,2 Aki Kido,3 Tsukasa Baba,1 Yumiko Yoshioka,1 Ken Yamaguchi,1 Noriomi Matsumura1 and Ikuo Konishi1 Departments of 1Gynecology and Obstetrics and 3Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto and 2Department of Diagnostic Pathology, Kumamoto University Hospital, Kumamoto, Japan
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. Key words: adenocarcinoma, clear cell, endometriosis, magnetic resonance imaging, retroperitoneal space
A uterus-like mass is considered a rare form of endometriosis, characterized by central endometriosis with cavity formation and smooth muscle proliferation surrounding the
Correspondence: Kaoru Abiko, MD, PhD, Department of Gynecology and Obstetrics, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan. Email: [email protected] Disclosure: None declared. Received 23 May 2014. Accepted for publication 6 September 2014. © 2014 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd
cavity.1 A total of 26 cases in English and 4 cases in Japanese scientific literature, including those arising in the ovaries, broad ligaments, or other organs, such as the small bowel or colon, have been reported previously,2–8 and only one study described the occurrence of a malignant tumor.8 Recently, we identified a case of clear cell carcinoma in a uterus-like mass of the retroperitoneal space. The patient had been followed with serial ultrasound and occasional MRI for 14 years until a demonstrated change suggested neoplastic occurrence of a malignant tumor. This case prompts a discussion regarding the diagnostic challenges and histogenesis of this rare entity.
CLINICAL SUMMARY A 53-year-old postmenopausal woman (gravida-1, para-0) presented with low back pain and was noted to have lumbar vertebrae disc herniation and a 5 cm pelvic mass by MRI and then was referred to our clinic. She had a past history of appendectomy and left salpingo-oophorectomy for appendicitis and a left ovarian tumor of unknown histology at 16 years of age and 32 years of age, respectively. On admission, ultrasonography demonstrated a cystic mass measuring 6 cm located on the right side of the pelvis. The cyst wall was smooth and 5-mm thick, and no solid component was identified. Serum CA125 and CA19-9 were 24 U/mL (normal,
