Choriocarcinoma: a rapidly progressive unusual tumor

A 41-year-old woman (G4P3) came to our emergency department with persistent nausea and metrorrhagia. The patient had a positive pregnancy test but denied recent sexual activity. She referred a voluntary abortion 6 months ago in another hospital and had abandoned further follow up appointments. β-hCG was significantly elevated (6780 U/L).

At ultrasonography it was identified an enlarged, heterogeneous uterus with echogenic mobile focus, suggesting the presence of air. It was not possible to differentiate the normal zonal anatomy. (Fig. 1) The uterus showed hypervascularization at Power Doppler (Fig. 2).

CT revealed a heterogeneous pelvic lesion, with predominant enhancement at the periphery, with multiple hypodense areas and central air (Fig. 3A and 3B) CT also demonstrated several pulmonary nodules, some of them surrounded by ground-glass opacity. There were also wedge-shaped juxta pleural consolidations in the right lung (Fig. 4A and B).

MRI depicted an infiltrative heterogeneous solid-cystic soft mass, with tortuous flow voids consistent with vessels, and loss of zonal anatomy with a left iliac lymph node (Fig. 5A and B). In T1-WI there were some hyperintense areas suggesting haemorrhage (Fig. 6). Post-contrast image showed intense heterogeneous enhancement. (Fig.7) The lesion demonstrated restricted diffusion. (Fig. 8).

During hospitalization, she developed hemorrhagic shock requiring radical hysterectomy.

In the postoperative period, the patient maintained hemodynamic instability that culminated in cardio-respiratory arrest and death. The histological examination revealed intermediate trophoblastic cells, without chorionic villi, myometrial and vascular invasion and large areas of haemorrhage, compatible with the diagnosis of choriocarcinoma. It was also confirmed the presence of several pulmonary metastases.

Choriocarcinoma results from malignant proliferation of trophoblastic tissue (namely, syncytiotrophoblast, cytotrophoblast and intermediate trophoblast), with absence of chorionic villi and direct invasion into the myometrium.

It is the most aggressive type of gestation trophoblastic neoplasia (GTN), with propensity to widely metastasize. It can also be non-gestational, occurring in the cervix, ovaries, testes or outside the reproductive tract. [1,2]

The majority of gestational of choriocarcinoma (50%) arise from hydatiform moles; 25% are associated with term/preterm gestation, and the remaining 25% follow abortion or tubal pregnancy.

Initial diagnosis of gestational trophoblastic disease is based on a combination of history, quantitative β-hCG titers, and pelvic sonography. [3] After that a metastatic workup with body CT and brain MRI is undertaken. [4]

On ultrasound, choriocarcinoma appears as an infiltrating heterogeneous lesion. It may be associated with enlarged cystic ovaries with theca lutein cysts secondary to markedly elevated β-hCG levels.

MRI is invaluable to assess extrauterine disease spread and complications. MR imaging shows a wide spectrum of appearances, reflecting the degree of haemorrhage and necrosis. [5]  

After contrast administration, the enhancement of the solid periphery of the tumour is lower than that observed in an invasive mole. Myometrial invasion is visible as high-signal-intensity foci within the myometrium, which demonstrate enhancement on postcontrast images. [6,7]

Chemotherapy is the mainstay of the management of choriocarcinoma due to exquisite sensitivity of most of these lesions, especially if detected early and classified correctly.

Appropriate management results in overall high cure rates (100% for low risk and 80–90% for high-risk group). [8,9]

The main imaging differential diagnoses are invasive mole and placental site trophoblastic tumour, which are often indistinguishable. However, invasive moles are locally invasive and nonmetastatic neoplasms. Placental site trophoblastic tumour is the rarest subtype of gestation trophoblastic disease, but usually is a slow-growing malignant tumour that metastasises to pelvic lymph nodes and, more rarely, causes distant lung metastasis.

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