epithelioid trophoblastic tumors ( ett ) are a rare form of gestational trophoblastic neoplasm ( gtn ) that is composed of a monomorphic population of chorionic - type intermediate trophoblastic cells.1 rarely , trophoblastic disease may develop independently of gestation in postmenopausal women.23 here , we describe a case of ett in a 56-year - old woman that developed 23 years after the patient 's last pregnancy . a 56-year - old korean woman ( gravida 2 , para 1 ) presented with a history of vaginal bleeding , which had started 3 months earlier . she was healthy at birth and had no history of an underlying disease or a clotting abnormality . in addition , there was no history of oral medication , pregnancy , or any other gynecological / surgical problem . she was postmenopausal for the past 10 years and her last childbirth was 23 years prior . laboratory results , including hemoglobin , coagulation panel , and biochemical tests , did not reveal any data of interest . her serum cancer antigen 125 ( ca-125 ) level was normal and other tumor markers were not performed preoperatively . a dilatation and curettage revealed blood clots , decidua with necrosis , and nodular proliferation of epithelioid trophoblasts ( fig . a total abdominal hysterectomy with bilateral salpingo - oophorectomy subsequently performed showed a slightly enlarged uterus ( fig . the tumor was composed of nests and cords , and had an expansive infiltrative pattern . the neoplastic cells had a moderate degree of pleomorphism and large eosinophilic cytoplasm , some of which had prominent nucleoli . the tumor showed cell necrosis with hyaline - like material , resembling a squamous cell carcinoma ( fig . 3 ) . immunohistochemistry showed a diffuse positive staining for p63 , placental alkaline phosphatase ( plap ) , and was highly positive for ki67 ( fig . postoperatively , serum -human chorionic gonadotropin ( -hcg ) level was < 0.8 miu / ml ( normal < 2 miu / ml ) . chest radiographs and computed tomography ( ct ) scans of the chest , abdomen , and pelvis showed normal finding . the patient did not receive chemotherapy . at the time of reporting , the patient was alive with no evidence of disease for 22 months after the surgery . it occurs mostly during reproductive age with a mean age of onset at 36.1 years.1 it is extremely rare in postmenopausal women.4 ett was first characterized in 1998 by drs . shih and kurman,1 who recognized it as a rare form of trophoblastic disease composed of intermediate trophoblast cells with features that made it distinct from placental site trophoblastic tumor ( pstt ) and choriocarcinoma . the intermediate trophoblast is thought to have a phenotype that is between that of the primitive cytotrophoblast and the terminally differentiated syncytiotrophoblast . the intermediate trophoblast is the primary cell type in an exaggerated placental site , placental site nodule , pstt , and ett . based on the anatomic location in the pregnant uterus , intermediate trophoblasts can be divided into villous , implantation site , and chorionic subtypes . the placental chorionic - type intermediate trophoblast has a nodular growth pattern and is thought to be the cell type of origin for lesions with a similar growth pattern , including placental site nodule and ett . in contrast , the placental implantation site intermediate trophoblast tends to have an infiltrative growth pattern , as does its neoplastic counterpart , pstt . etts are considered a neoplasm composed of chorionic - type intermediate trophoblasts based on histologic characteristics , immunohistochemical expression , and polymerase chain reaction analysis.156 ett is usually associated with a prior gestational event . these antecedent gestational events include full - term deliveries , spontaneous abortion , hydatidiform mole , and choriocarcinoma . the interval between the preceding gestational event and the diagnosis of ett ranges from 1 to 30 years.1 our patient had a full - term delivery 23 years before the diagnosis . serum -hcg levels in most cases of ett are raised.1 a high level of serum -hcg in ett is associated with a large mass and high mitotic activity.7 the low level of serum -hcg in our patient may have been due to a small tumor volume or may have been a postoperative result . as eosinophilic hyaline - like material resembling keratin is an integral part of ett , ett can be easily misinterpreted as a keratinizing squamous cell carcinoma of the cervix.1 several cases have been reported that were initially misdiagnosed as cervical squamous carcinomas because of in situ cervical spread.8 extra - uterine ett can be especially difficult to diagnosis if it presents as a metastatic lesion . if the lesion was located in the ovary and distant lymph node , other malignant disease should be excluded.910 the differential diagnosis of ett includes other gtns , such as choriocarcinoma and pstt . immunohistochemical studies can help differentiate ett from choriocarcinoma and pstt . in ett , both -hcg and human placental lactogen ( hpl ) exhibit focal reactivity.11 this is in distinct contrast to the staining patterns seen in choriocarcinoma and pstt . in choriocarcinoma , -hcg is diffusely positive , highlighting numerous syncytiotrophoblastic cells , whereas hpl positive cells are less conspicuous . the converse is typical of pstt , in which there is diffuse positive staining for hpl while staining for -hcg tends to be focal or absent . p63 is expressed in chorionic - type intermediate cells ( ett ) , but not in pstt.12 we report this case due to the rarity of trophoblastic tumors in postmenopausal women and the associated diagnostic dilemma . ett should be considered in the differential diagnosis when the postmenopausal patient presents with vaginal bleeding .
epithelioid trophoblastic tumor ( ett ) is a rare gestational trophoblastic neoplasm composed of intermediate trophoblasts . 
 most cases of ett are reported in women of reproductive age following a prior gestation within 2 weeks to 30 years . 
 ett is extremely rare in postmenopausal women . 
 it is commonly misdiagnosed as a poorly differentiated carcinoma or another type of gestational trophoblastic tumor . 
 we report a case of ett in a 56-year - old woman that developed 23 years after the patient 's last pregnancy .