A Case Series of Five Patients With Pure or Mixed Gestational Epithelioid Trophoblastic Tumors and a Literature Review on Mixed Tumors

Ka Yu Tse, MRCOG; Keith Wan Hang Chiu, FRCR; Karen Kar Loen Chan, FRCOG; Mandy Man Yee Chu, MRCOG; Siew Fei Ngu, MRCOG; Annie Nga Yin Cheung, FRCPath; Hextan Yuen Sheung Ngan, FRCOG; Philip Pun Ching Ip, FRCPath


Am J Clin Pathol. 2018;150(4):318-332. 

In This Article

Abstract and Introduction


Objectives: To review the clinicopathologic features of five patients with epithelioid trophoblastic tumor (ETT).

Methods: Characteristics of patients diagnosed with ETT in 2000 to 2012 were reviewed.

Results: Among 190 patients with gestational trophoblastic neoplasia (GTN), two had pure ETT and three had mixed ETT and choriocarcinoma. The median age was 32.5 years. All the patients had localized disease in the uterus. One patient with pure ETT had a recurrence in the ureter 6 years after the initial treatment. Another patient with pure ETT had two full-term deliveries after fertility-sparing surgery. The three patients with mixed tumors had chemotherapy for GTN before their diseases were completely treated by hysterectomy. At a median follow-up of 102 months, all patients survived.

Conclusions: ETT is indolent. Recurrence can happen, but the risk factors are not clear. When patients with GTN fail to respond to chemotherapy, the possibility of mixed GTN should be considered.


Epithelioid trophoblastic tumor (ETT) is rare, with only about 110 cases reported in the literature.[1] Mazur and Kurman[2] first described the entity in 1994, and Shih and Kurman[3] elaborated on it further in 1998. ETT, a tumor derived from chorionic laeve-type extravillous trophoblasts, is characterized by uniform monomorphic nests and cords of mononucleated intermediate trophoblastic cells, which are surrounded by extensive necrosis and are associated with an eosinophilic hyaline-like matrix, creating a "geographical" pattern.[4] Some scholars believed ETT was the result of a malignant transformation from a preexisting placental site nodule (PSN),[5,6] although it is noteworthy that most PSNs do not progress to ETT, and the former do not require hysterectomy. Nearly half of the ETTs are located in the lower uterine segment, or endocervix, and it is therefore conceivable they may be mistaken as squamous cell carcinoma of the cervix.[7–9] Most ETTs occur in the reproductive age group, and the average age is 36.1 years (range, 15–48 years).[3] Patients often have symptoms resembling those in placental site trophoblastic tumor (PSTT). Because both types of tumors are slow growing, the patients can be asymptomatic.[1] About 60% to 70% of the patients have abnormal vaginal bleeding, and some may have amenorrhea.[10] About 30% to 50% of the patients have symptoms related to metastasis, such as shortness of breath and hemotypsis.[1,6] Rarely, they might present with nephrotic syndrome and virilization. There is no unique staging system for PSTT and ETT. Since most PSTT and ETT are diagnosed with the tumor confined inside the uterus, and the serum human chorionic gonadotropin (hCG) level is usually only mildly elevated, the usual International Federation of Obstetrics and Gynecology (FIGO) staging system and the World Health Organization (WHO) scoring system[11] may not be applicable in these two entities. Similar to PSTT, metastasis and death could occur in about 25% and 10% of patients with ETT, respectively.[3] It is also not sensitive to chemotherapy, and the mainstay treatment is hysterectomy.[1,12] We report five cases of pure or mixed ETT from our gestational trophoblastic neoplasia (GTN) referral center in Hong Kong.