The histopathology of trophoblastic tumours

Clinical presentation and diagnosis of Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD) is a heterogeneous group of pregnancy-related disorders characterized by abnormal proliferation of trophoblastic tissue. It encompasses the premalignant partial and complete hydatidiform mole but also the malignant invasive mole, choriocarcinoma, placental-site trophoblastic tumor, and epithelioid trophoblastic tumor. The clinical presentation changed to earlier detection after the introduction of first trimester ultrasounds. Patients are often asymptomatic, but vaginal bleeding continues to be the most common presenting symptom. Other symptoms can develop in the case of metastatic disease. Ultrasound, serum human chorionic gonadotrophin, and sometimes additional imaging such as CT, MRI, or PET can confirm the diagnosis and stage of disease. Familiarity with the pathogenesis, classification, imaging features, and treatment of GTD facilitates diagnosis and appropriate management.

Intrauterine fetal death with subsequent quill exfoliation and dissemination in a North American porcupine (Erethizon dorsatum)

An adult female, wild North American porcupine (Erethizon dorsatum) presented with bilateral cataracts and naso-ocular discharge. A pregnancy was identified by radiography with a near-full-term fetus, which was delivered stillborn 4 wk later with hard, developed quills. At that time, a repeated examination and further imaging, including computed tomography, demonstrated a uterine mass that was identified as a choriocarcinoma following ovariohysterectomy. Additionally, numerous exfoliated quills were discovered throughout the abdomen, most of which were removed during the surgical procedure. Ultimately, development of peritonitis despite medical care led to the porcupine's death. Necropsy confirmed a wide migration of the quills with extensive serosal adhesions and granulomas affecting liver, lungs, urinary bladder, kidneys, and gastrointestinal tract.

Pathology of gestational trophoblastic diseases

Gestational trophoblastic disease (GTD) is a heterogeneous group of diseases. This used to include partial and complete hydatidiform moles, invasive mole, choriocarcinoma and placental site trophoblastic tumour. In recent years, new entities, including epithelioid trophoblastic tumour, have been added to this family. Non-neoplastic and neoplastic lesions derived from implantation site and chorion intermediate trophoblast have been gaining attention in the literature. New markers for trophoblasts have been identified facilitating histological diagnosis in cases with unusual clinical or pathological features. It is worth noting that histological distinction between hydropic abortion and partial mole and between complete and partial moles, especially at early gestational age, may be difficult. It may not be possible to predict progress of the heterogeneous group of GTD from histopathological features, except probably in placental site trophoblastic tumour. Alternative biological markers may be explored for better patient management.

MR appearance of placental site gestational trophoblastic neoplasm

The magnetic resonance imaging (MRI) findings of a patient with placental site trophoblastic tumor are presented. In this patient, a small focal mass distorting the junctional zone and invading the myometrium was identified. Due to the aggressive nature of this neoplasm and the difficulty in detecting it clinically, MRI may represent a useful tool in the evaluation of such tumors.

The significance of proliferating cell nuclear antigen in human trophoblastic disease: an immunohistochemical study

The expression of proliferating cell nuclear antigen (PCNA) in human trophoblastic disease was assessed immunohistochemically in tissue from 29 spontaneous abortions, 33 partial moles, 40 complete moles and 23 choriocarcinomas using the monoclonal antibody PC10. PCNA immunoreactivity occurred predominantly in the cytotrophoblasts in each of the four types of tissues. Quantitative analysis showed that the choriocarcinoma group gave a statistically significant higher PCNA index than the other three. There was no significant difference between the groups of spontaneous abortion, partial or complete mole. Sixteen of the 73 patients with partial and complete moles developed persistent gestational trophoblastic disease and there was no significant difference between the patients requiring chemotherapy and those who did not. We conclude that choriocarcinoma has a significantly higher PCNA proliferative index whilst hydatidiform moles cannot be distinguished from abortions by such analysis. The PCNA index does not appear to be useful in predicting the progression of molar pregnancies to persistent trophoblastic diseases.

Choriocarcinoma following a partial hydatidiform mole: a case report

Hydatidiform moles are classified as partial or complete by histologic criteria (Am J Obstet Gynecol 131:665-671, 1978 and Am J Obstet Gynecol 132:20-27, 1978). While persistent gestational trophoblastic tumors follow both types, there remains controversy as to whether the malignant extreme of gestational trophoblastic tumors, choriocarcinoma, can follow a partial hydatidiform mole (Am J Obstet Gynecol 127:167-170, 1977 and Arch Gynecol 234:161-166, 1984). In this instance, a 37-year-old woman presented with a partial hydatidiform mole that persisted and was treated with one course of chemotherapy. She attained a remission for 10 months, when a routine follow-up examination revealed an asymptomatic rise in serum beta-human chorionic gonadotropin from baseline to 14,600 mIU/mL. Dilatation and curettage revealed abundant avillous cytotrophoblast and syncytiotrophoblast with marked atypia, diagnostic of choriocarcinoma. Flow cytometry of paraffin blocks of both specimens showed the partial hydatidiform mole to be triploid and the choriocarcinoma diploid. The patient had no evidence of metastatic disease and was successfully treated with multiple-agent chemotherapy.

Placental site trophoblastic tumor: immunohistochemical and nuclear DNA study

A rare case of placentae site trophoblastic tumor (PSTT) studied by immunohistochemistry and nuclear DNA analysis is reported. The patient, a 24-year-old Japanese female, complained of amenorrhea. Dilatation and curettage revealed a small specimen that contained trophoblastic cells and caused intractable bleeding. Pelvic sonography revealed a 5-cm mass in the posterior uterine wall with multiple cystic lesions of several sizes. The cystic lesions were shown to be dilated vessels by magnetic resonance imaging (MRI) and digital subtraction angiography (DSA). Serum beta-hCG (beta subunit of human chorionic gonadotropin) was 3.7 ng/ml. Total abdominal hysterectomy revealed a well-circumscribed, yellow, soft mass in the posterior uterine wall. Microscopic findings were consistent with PSTT and the mitotic count was extremely low. Immunohistochemically, most of the tumor cells were intensely stained with human placental lactogen, whereas few were stained with human chorionic gonadotropin. The nuclear DNA content of the trophoblastic cells showed a sharp peak at the triploid range coexistent with a few cells of higher ploidy. This is the first report of sonographic findings and nuclear DNA analysis by spot cytometry in a case of PSTT.

Gestational trophoblastic tumors

Gestational trophoblastic tumor is a term applied to invasive mole, choriocarcinoma, and placental-site trophoblastic tumor. The overall cure rate in the treatment of these gestational trophoblastic tumors now exceeds 90%. This high success rate is the result of (1) inherent sensitivity of trophoblastic tumors to chemotherapy, (2) ability to monitor therapy effectively with the use of human chorionic gonadotropin as a tumor marker, and (3) identification of prognostic factors which allows categorization of patients into high- and low-risk groups for selection of treatment. Virtually all patients with nonmetastatic and low-risk metastatic disease can be cured using single-agent methotrexate or Actinomycin-D chemotherapy. Intensive therapy with combination chemotherapy including etoposide, high-dose methotrexate and Actinomycin D and, where indicated, adjuvant radiotherapy and surgery has resulted in cure rates of 80-90% in patients with high-risk metastatic disease. The factors which are most important in determining response to treatment are: (1) clinicopathologic diagnosis of choriocarcinoma, (2) metastases to sites other than the lung or vagina, (3) number of metastases, (4) previous failed chemotherapy, and (5) WHO score greater than or equal to 8.

Genetically different cell subpopulations in hydatidiform moles. A study of three cases by RFLP, flow cytometric, cytogenetic, HLA, and morphologic analyses

Most investigators find a good correlation between the morphologic and cytogenetic classification of hydatidiform moles (HM), but exceptions have been noted. We have examined three cases of HM, using chromosome marker analysis on cultured cells, human leukocyte antigen typing on cultured and uncultured tissue, and restriction fragment length polymorphism (RFLP) analysis and flow cytometry on uncultured cells. In one morphologically partial mole, only one cell population (triploid) was found and data obtained by the above-mentioned techniques were concordant. The other two moles, which were classified morphologically as complete, consisted of several cell subpopulations differing in DNA content. In both cases only one cell population was disclosed by cytogenetic investigation. In one case, the cytogenetic analysis indicated that the cultured cells were near triploid with paternal chromosomes exclusively, whereas RFLP analysis showed that maternal X chromosomal alleles were present in the mole. The present findings demonstrate that some HMs contain cellular subpopulations with differing DNA content. One explanation for discordance between cytogenetic and morphologic classification may thus be the detection of only one cell subpopulation when karyotyping.

Gestational trophoblastic tumors

Although virtually 100% of women who develop gestational trophoblastic tumors enter a long-term complete remission, there are many aspects of trophoblastic disease that arouse interest. Epidemiological studies have shown a large geographical variation in the percentage of conceptions that result in a hydatidiform mole and have stimulated studies on the immunological differences of the low and high risk populations. Chromosomal analysis is now complementing the pathological differentiation between complete and partial moles. There is still debate as to which factors are positively associated with the progression of a hydatidiform mole through invasive mole to choriocarcinoma. There are also considerable differences in the proportion of molar patients receiving chemotherapy in different centers. In addition to these topics, this article will review several recently introduced treatment regimens which show improved results with reduced toxicity.

Ectopic vaginal trophoblast in association with a partial mole

A case of ectopic vaginal trophoblast in association with a blighted ovum showing hydropic degeneration is presented. This combination satisfied the histological criteria of Szulman and Surti for inclusion as a partial mole. Subsequent follow-up revealed non-progression of the condition. The problems of obtaining a satisfactory classification for proliferative trophoblastic lesions are outlined.

Discrepancies in the histological diagnosis of hydatidiform mole

Sections of tissue from 256 patients on which a histological diagnosis of hydatidiform mole had been made were reviewed by a visiting pathologist. There was agreement between the reporting pathologists and the visiting pathologist in only 55.1 per cent of cases, a less severe diagnosis was made by the visiting pathologist in 42.2 per cent of cases. The disagreement was as high as 66.6 per cent with pathologists who rarely worked in the gynaecological field. This study casts serious doubt on the consistency of the histological diagnosis of hydatidiform mole made in any one laboratory and between different laboratories. It is suggested that in epidemiological studies the diagnosis should be made by a panel of pathologists using strict histological criteria and in an individual laboratory diagnosis should be made or confirmed by a pathologist experienced in gynaecological pathology.

Trophoblastic pseudotumor of the uterus: case report and ultrastructure

A trophoblastic pseudotumor occurring in a young woman 6 months after a normal pregnancy is reported. Ultrastructural investigation demonstrated a close structural relationship between the infiltrating cells and those of the trophoblastic components of the normal human placenta, especially those seen in the primary villi of the developing placenta.