Masaki Mandai1, Yutaka Osuga2, Tetsuya Hirata2, Takayuki Enomoto3, Hidekatsu Nakai4, Ritsuo Honda5, Fuminori Taniguchi6, Hidetaka Katabuchi5. 1. Department of Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Japan. 2. Department of Obstetrics and Gynecology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. 3. Department of Obstetrics and Gynecology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan. 4. Department of Obstetrics and Gynecology, Kindai University Faculty of Medicine, Osaka-Sayama, Japan. 5. Department of Obstetrics and Gynecology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan. 6. Department of Obstetrics and Gynecology, Tottori University Faculty of Medicine, Yonago, Japan.
Abstract
AIM: Endometriosis mostly affects the ovary but can also be present outside of the ovary including the pelvic peritoneum, intestine, urinary tract and lung. In case of ovarian endometriotic cyst, an increased risk of ovarian cancer, especially of clear cell and endometrioid histology, has been reported. However, because of the rarity, cancer occurrence from endometriosis at less common sites/rare sites is poorly understood. METHODS: We conducted a nationwide survey on the less common/rare site endometriosis in 3539 authorized facilities in Japan. We requested to complete a case report form for each case, including information on the history of endometriosis, treatment for endometriosis, type of surgery, involved site(s) of cancer and endometriosis, histology of cancer, chemotherapy and outcome. RESULTS: Out of 1397 confirmed cases of less common/rare site endometriosis, 11 cases of rare site endometriosis-associated cancer (RSEAC) were reported: seven of them were associated with intestinal endometriosis, three were associated with urinary tract endometriosis and one was associated with umbilical endometriosis. Interestingly, the histology was endometrioid in seven (64%) cases, and serous, seromucinous borderline, clear cell and mucinous in one case each (10%), differing from the case of ovarian endometriosis-associated cancer, in which clear cell carcinoma are more common. CONCLUSION: Our nationwide survey on RSEAC has revealed that: (i) the incidence of malignant transformation may be lower than ovarian endometriosis, (ii) malignant transformation from endometriosis outside the abdominal cavity may be extremely rare and (iii) the histology of RSEAC is predominantly endometrioid type, suggesting an association of a hormonal effect.
AIM: Endometriosis mostly affects the ovary but can also be present outside of the ovary including the pelvic peritoneum, intestine, urinary tract and lung. In case of ovarian endometriotic cyst, an increased risk of ovarian cancer, especially of clear cell and endometrioid histology, has been reported. However, because of the rarity, cancer occurrence from endometriosis at less common sites/rare sites is poorly understood. METHODS: We conducted a nationwide survey on the less common/rare site endometriosis in 3539 authorized facilities in Japan. We requested to complete a case report form for each case, including information on the history of endometriosis, treatment for endometriosis, type of surgery, involved site(s) of cancer and endometriosis, histology of cancer, chemotherapy and outcome. RESULTS: Out of 1397 confirmed cases of less common/rare site endometriosis, 11 cases of rare site endometriosis-associated cancer (RSEAC) were reported: seven of them were associated with intestinal endometriosis, three were associated with urinary tract endometriosis and one was associated with umbilical endometriosis. Interestingly, the histology was endometrioid in seven (64%) cases, and serous, seromucinous borderline, clear cell and mucinous in one case each (10%), differing from the case of ovarian endometriosis-associated cancer, in which clear cell carcinoma are more common. CONCLUSION: Our nationwide survey on RSEAC has revealed that: (i) the incidence of malignant transformation may be lower than ovarian endometriosis, (ii) malignant transformation from endometriosis outside the abdominal cavity may be extremely rare and (iii) the histology of RSEAC is predominantly endometrioid type, suggesting an association of a hormonal effect.