Hydatidiform mole refers to an abnormal pregnancy characterized by varying degrees of trophoblastic proliferation and vesicular swelling of placental villi associated with an absent or an abnormal fetus and or embryo [
3]. It has been reported that the hydatidiform moles that erode the wall of the uterus, burrow into the myometrium and may even burst though the uterus into the peritoneum are called invasive moles [
4,
5]. Local metastasis and invasion is common for invasive moles. Metastasis may occur in the lung, pelvis and vagina. Rare sites include the gastrointestinal tract, spleen, and kidney. Central nervous system metastasis is rare. It is often fatal because of the high risk of intracerebral hemorrhage, neurological deterioration, and death [
4]. Invasive mole is often diagnosed clinically rather than pathologically based on persistent hCG elevation after molar evacuation and is frequently treated with chemotherapy without a histopathologic diagnosis [
2]. Therefore, the intracerebral lesion in our patient should be attributed to the metastasis of an invasive mole. The usual clinical interpretation of homonymous quadrantanopsia is the effect of lesions of the optic radiations course between the optic tract and the striate cortex. Superior homonymous defects are generally associated with temporal lobe lesions, whereas inferior defects commonly result from lesions of the parietal lobe. Cerebrovascular disease is a potential cause of homonymous quadrantanopsias. Rampini P
et al. [
6] presented a case of left quadrantanopsia secondary to traumatic subclavian steal syndrome. Infarction of the ventromedial aspect of the inferior occipital lobe [
7] and striate cortex [
8] leading to homonymous superior quadrantanopsia have been reported in the literature as well. Association with non-occlusive vascular events related to vertebrobasilar hypoperfusion rather than embolization is also not uncommon. In 1962, Smith [
9] reviewed a series of homonymous hemianopia cases. He found that occipital lobe lesions are the most common cause of hemianopia and are more frequent in men than women. Vascular lesions are the most common cause of occipital lobe field defects compared to tumors. Cerebral metastasis of tumor is also a common cause leading to this kind of special visual field defect. Groom
et al. [
10] presented an optic tract syndrome case with homonymous hemianopia caused by metastasis to the lateral geniculate body and optic tract secondary to metastatic breast cancer. The pituitary gland is an uncommon site for metastasis. Baehring
et al. [
11] reported a case of heteronymous inferior quadrantanopsia of hypothalamic mass lesion with extension into the pituitary fossa.