Malignant disease in pregnancy

Cancer in pregnancy is rare, affecting less than 1 in 1,000 live births. It may be specific to pregnancy (gestational trophoblastic disease) or incidental to it, the less infrequent conditions being melanoma, lymphoma, and cervical malignancy. Tumours of the uterine cervix, ovary, breast, or thyroid can metastasize to the placenta, but not to the fetus. Gestational trophoblastic disease arises from fetal chorion and is a malignant transformation of the placenta. Melanoma and haematological tumours, which also can invade the placenta, may cross into the fetal circulation. Pregnancy may cause enlargement of a pituitary tumour and a previously silent tumour may present with symptoms in pregnancy. Rare cases of colonic and neurological cancers developing in pregnancy have also been reported.