Choriocarcinoma is an aggressive, highly vascular tumour. When it is associated with gestation, it is often considered part of the spectrum of gestational trophoblastic disease; it is then termed gestational choriocarcinoma. When it occurs in the absence of preceding gestation, it is termed non-gestational choriocarcinoma (these occur most often in the ovary or testis).

Epidemiology

Depends on the site of origin of the tumour. In females, it may occur during or outside of pregnancy; non-gestational choriocarcinoma of the ovary typically occurs in prepubertal girls and postmenopausal women. Testicular choriocarcinomas are usually present in male patients between ages 15 and 30 ⁹.

Gestational choriocarcinoma has an incidence rate of 1 in 20,000 - 30,000 pregnancies with 50% arising from molar pregnancies. 25% arise from previous abortions and ~22% occur following normal pregnancies ¹⁰.

Pathology

In the classic case of gestational choriocarcinoma, the tumour is derived from chorionic epithelium.

Location

Typically arises in association with reproductive organs:

• uterus: choriocarcinoma of the uterus

• cervix ⁸

• ovary: choriocarcinoma of the ovary

  • pure primary ovarian choriocarcinoma ¹

• testes: testicular choriocarcinoma

Primary occurrence outside the reproductive system has been reported but is extremely rare. Such sites include:

• brain: primary intracranial choriocarcinoma

• lung: primary pulmonary choriocarcinoma (PPC)

• pulmonary arteries ⁵

• stomach ^6,7

• the small intestine

• pancreas ⁶

Trophoblastic cells have an affinity for blood vessels and therefore the tumours have a tendency to metastasise through the haematogenous route.

Choriocarcinoma is one of the causes of cannonball metastases to the lungs.

Markers

High levels of βhCG are usually seen in cases of choriocarcinoma.

Radiographic features

Imaging features of a primary tumour are dependent on location: see individual subtypes under "location" above.

Treatment and prognosis

The tumour is aggressive in its behaviour and metastases are frequent, with the lungs being a common site of metastasis. Despite its aggressiveness, it is generally highly chemosensitive and carries a much better cure rate than other comparable malignancies.

Complications

A significant proportion of the complications arises from haemorrhage due to high vascularity in either a primary tumour or its metastases.