[Malignant transformation of ovarian endometriosis: a clinicopathologic analysis of 49 cases].

BACKGROUND & OBJECTIVE: Ovarian endometriosis is a common and benign, but progressive disease. We aimed to investigate the clinicopathologic of ovarian endometriosis with malignant transformation and to evaluate the expression differences of estrogen receptor (ER) and progesterone receptor (PR) between ovarian endometriosis samples with and without malignant transformation. METHODS: Clinicopathologic data of 49 ovarian endometriosis patients with malignant transformation were reviewed. The expression of ER and PR in the 49 specimens of ovarian endometriosis with malignant transformation (transformation group) and 49 specimens of ovarian endometriosis without malignant transformation (control group) were detected by immunohistochemistry and compared statistically. RESULTS: The 49 ovarian endometriosis patients were aged of 29-70 years with a median of 49 years. The major initial manifestation was pelvic masses. B-ultrasound examination showed mixed cystic and solid masses in the pelvic cavity. Macroscopically, the ovarian masses were cystoid and parenchymal with diameters of 4.0-20.0 cm; the cysts possessed thick and fibrous walls (in brown or yellow) and contained chocolate-like fluid or semi-fluid materials; the parenchymal part was tender papillary nodules with diameters of 0.5-15.0 cm. Microscopically, the ectopic endometrium proliferated and transformed to atypical hyperplasia and carcinoma. The positive rates of ER and PR proteins were significantly lower in transformation group than in control group (20.4% vs. 95.9%, 14.3% vs. 95.9%, P < 0.05). CONCLUSIONS: The malignant transformation of ovarian endometriosis is likely to occur in peri-menopausal women. Clinical manifestations, B-ultrasound examination and pathologic examination are valuable for diagnosis. The absence of ER and PR protein expression in endometriosis may help to diagnose malignant transformation of ovarian endometriosis.