Three cases of clear‐cell adenocarcinoma arising from endometrioma during hormonal treatments

• Published in: The journal of obstetrics and gynaecology research 2018-09, Vol.44 (9), p.1850-1858
• Main Authors: Yoshino, Osamu, Minamisaka, Takashi, Ono, Yosuke, Tsuda, Sayaka, Samejima, Azusa, Shima, Tomoko, Nakashima, Akitoshi, Koga, Kaori, Osuga, Yutaka, Saito, Shigeru
• Format: Article
• Language: English
• Subjects: Adenocarcinoma; Adenocarcinoma, Clear Cell - etiology; Adult; endometrioma; Endometriosis; Endometriosis - complications; Endometriosis - drug therapy; Estrogen receptors; Female; Gonadotropin-releasing hormone; HER‐2; hormonal therapy; Hormone Antagonists - adverse effects; Hormone replacement therapy; Humans; Immunohistochemistry; Middle Aged; Ovarian cancer; Ovarian Neoplasms - etiology; Progesterone; Progestin; Surgery; Tamoxifen
• ISSN: 1341-8076; 1447-0756
• DOI: 10.1111/jog.13702

Endometrioma is known to be an occurrence site of ovarian cancer, but there is no evidence on how to reduce the risk of canceration. Here, we report three cases of ovarian cancer arising from endometrioma during hormone therapies of GnRH analogue and tamoxifen, low‐dose estrogen‐progestin (LEP) and dienogest. In all cases, each hormonal treatment was effective in shrinking the size of the endometrioma. During hormonal treatments, solid parts inside endometrioma were observed, which was followed by surgery. The histology of the solid parts was clear‐cell adenocarcinoma in all cases. An immunohistochemistry study demonstrated that the estrogen receptor (ER) and progesterone receptor (PR) were positive in the endometriosis part but negative in the cancer part, while the human EGF receptor (HER) 2 was negative or very weak in the benign part and positive in the malignant part in all three cases. Even though hormonal treatments seem to be effective to regulate endometrioma, careful observation is needed to follow‐up patients with endometrioma.