To describe a case of replaced posterior cerebral artery (PCA) in which all branches of the PCA arose from the anterior choroidal artery (AChA) with an early branching temporal artery.

An 83-year-old man with cerebral infarctions underwent cranial magnetic resonance (MR) imaging and MR angiography using a 3-Tesla scanner. MR angiography was performed using a standard 3-dimensional time-of-flight technique.

A large anomalous artery arose from the supraclinoid segment of the right internal carotid artery (ICA) and supplied all branches of the right PCA, mimicking fetal-type PCA. The temporal branch arose from the proximal segment of this artery. In MR angiographic source images, a tiny artery arose from the right ICA proximal to the origin of the anomalous artery, indicating a hypoplastic right posterior communicating artery (PCoA). Thus, we concluded that the anomalous artery was a replaced PCA; all branches of the PCA arose from the AChA.

We present a case involving a replaced PCA with an early branching temporal artery, as seen on MR angiography. Careful observation of MR angiographic source images is useful for identifying small arteries. To our knowledge, this is the first report of this combined variation in the relevant English-language literature.