Epithelioid trophoblastic tumor: comparative genomic hybridization and diagnostic DNA genotyping

Arising from the putative chorionic-type intermediate trophoblast, epithelioid trophoblastic tumor is a recent addition to the spectrum of gestational trophoblastic diseases. Frequently, the tumor involves the uterine cervix and is misdiagnosed as invasive squamous-cell carcinoma. The pathogenesis of the tumor is poorly understood, and its molecular analysis is essentially lacking. This study was designed to explore chromosomal alterations in epithelioid trophoblastic tumor and to use DNA genotyping to demonstrate its trophoblastic origin, therefore separating the tumor from its mimics of the maternal origin. Five cases of epithelioid trophoblastic tumors were included in this study and paired DNA samples from the tumor and normal tissue were extracted from paraffin-embedded archival materials. The status of chromosomal alterations was analyzed by comparative genomic hybridization using conventional metaphase chromosome preparations. The parental genetic contribution was determined by DNA genotyping analysis using AmpFISTR Identifiler Amplification system (Applied Biosystems Inc.). Comparative genomic hybridization analysis was successful in three cases analyzed, all of which showed a balanced chromosomal profile without detectable gain or loss of the genome. DNA genotyping was informative in four epithelioid trophoblastic tumor involving anatomic locations including the cervix (two cases), endomyometrium (one case) and lung (metastatic, one case). All four cases were found to have unique paternal alleles, confirming the trophoblastic nature of the tumors. In summary, chromosomal alterations detectable by conventional comparative genomic hybridization are not features of epithelioid trophoblastic tumors. In difficult cases, the presence of the paternal alleles demonstrated by DNA genotyping is a powerful diagnostic application in separating an epithelioid trophoblastic tumor from its maternal mimics, particularly the far more common squamous-cell carcinoma of the uterine cervix.

P57kip2 immunohistochemical expression and ultrastructural findings of gestational trophoblastic disease and related disorders

Gestational trophoblastic disease (GTD) is a unique spectrum of diseases ranging from complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and invasive mole (IM) to choriocarcinoma (CC). Placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) have been classified as related disorders. Mesenchymal dysplasia (MD) may be misdiagnosed as PHM; however, it is said to have a quite different histogenesis from PHM. P57kip2 is the protein product of a paternally imprinted or maternal gene that inhibits cyclin-dependent kinases (CDK), thus serving to inhibit cell proliferation and to suppress tumor growth. Its lack of expression in trophoblastic disease plays a role in its abnormal proliferation and differentiation. In this study, P57kip2 immunostaining was absent in the trophoblastic layers of CHM and was positive in the trophoblast layer of nonmolar villi and MD. Ultrastructure of complete molar cystic villi showed tree-like branching of microvillous processes and intracytoplasmic lacunae without capillaries in the stroma, whereas MD contained many newly formed blood vessels and collagen. Also, large lacunae with microvilli and polymorphic nuclei of syncytiotrophoblast cells with well-developed organelles were observed in IM. Lung ETT following CHM and normal deliveries showed two types of large mononuclear cells and binuclear cells with abundant organelles and bundles of intermediate-type filaments in the stroma.

Clinicopathologic characteristics and subsequent pregnancy outcome in 139 complete hydatidiform moles

OBJECTIVE

The most common form of gestational trophoblastic disease is the complete hydatidiform mole (CHM). The study reports our experience of clinicopathologic characteristics and subsequent pregnancy outcome of patients with CHM.

STUDY DESIGN

One hundred fifty-one subsequent cases with initial diagnosis of CHM were re-evaluated histopathologically. Clinical characteristics, the need for chemotherapy and subsequent pregnancy outcome were evaluated.

RESULTS

Twelve out of 151 cases were re-evaluated as hydropic abortion, as partial hydatidiform moles or were insufficient for morphologic examination and therefore excluded from further analysis. The leading clinical symptoms of the remaining 139 cases were irregular vaginal bleeding (67%) and uterine enlargement (41%). Twenty-six patients (19%) required chemotherapy because of gestational trophoblastic neoplasia (GTN; low-risk: 23 out of 26). All patients were cured successfully. The subsequent pregnancy rate was 15% (21/139). Five patients suffered from abortions, 12 women delivered a healthy offspring. Four women presented with recurrent CHM with a spontaneous normalization of HCG levels after D&C.

CONCLUSIONS

The clinical and morphologic diagnosis of CHM is a challenge, and diagnosis as well as treatment should be multidisciplinary and centralised. One fifth of CHM are at risk of a GTN, but the cure rate is 100% with adequate management. Pregnancy outcome following CHM is complicated by an increased risk of abortion.

Prognostic value of trophoblastic proliferation in complete hydatidiform moles in predicting persistent disease

The clinical outcome of patients with complete hydatidiform moles (CHM) is variable. The correlation between trophoblastic proliferation and development of persistent disease was evaluated. A hundred and fifty-one cases with the initial diagnosis of CHM were re-evaluated histopathologically. The need for chemotherapy and occurrence of metastatic disease was correlated with the histologic grade using a three-level score. Twelve out of 151 cases were re-evaluated as hydropic abortion, partial moles, or were insufficient for morphologic examination, representing a diagnostic agreement of 92%. A total of 63.4% of the CHM presented with low trophoblastic proliferation with focal areas of slight hyperplasia (grade 1), and 23.7% with moderate proliferation with slight anaplasia and medium-sized sheets of free trophoblast in between the villies (grade 2). In all, 12.9% of the cases showed marked hyperplasia with marked anaplasia and involvement of nearly all villies, as well as a large amount of intervillous trophoblastic sheets (grade 3). Twenty-six of the CHM (19%) required chemotherapy. Grade 3, on histology, showed a positive correlation with the necessity of chemotherapy (p=0.04), but not with the occurrence of metastatic disease. Histomorphology might predict the risk of persistent disease, indicating the necessity for closer a follow-up, but further studies are required.

Epithelioid trophoblastic tumor: clinicopathological features with an emphasis on uterine cervical involvement

We report on the clinical and histological features of five cases of epithelioid trophoblastic tumor, with an emphasis on its involvement of the uterine cervix. All five patients were of reproductive age (median age 38.4 years) and all, except one, presented with vaginal bleeding 3 to 18 years after the most recent pregnancy. One patient presented with amenorrhea. Elevation of serum human chorionic gonadotropin (hCG) was seen in four cases. Pathologically, the tumor involved endocervix in three cases and involved uterine corpus in another two. All five tumors were invasive, nodular lesions consisting of epithelioid intermediate trophoblastic cells that were mononuclear with abundant eosinophilic cytoplasm, along with zones of hyaline material and necrotic debris. In three cases of cervical involvement, the neoplastic cells focally replaced endocervical surface and glandular epithelium, simulating high-grade squamous intraepithelial lesions. Immunohistochemically, all five tumors displayed focal positivity for human placental lactogen and hCG. Positive nuclear staining of p63 was seen in all five cases. All patients received total hysterectomy and various regimes of adjuvant chemotherapy. Three patients survived the tumor with no recurrences or metastases with follow-up periods of 3, 7 and 16 years. One patient is currently alive with lung metastasis 1 month after the surgery. One patient died of tumor metastasis 8 months after the diagnosis. In summary, with its unusual ability to simulate an invasive squamous cell carcinoma and other epithelioid neoplasms, epithelioid trophoblastic tumor frequently poses a diagnostic challenge, especially when involving the uterine cervix. High index of suspicion and an awareness of elevation of serum chorionic gonadotropin are crucial in reaching a correct diagnosis.