As is the case with penetrating arteries into the basal ganglia, the penetrating arteries from the basilar artery extending into the pons are subject to lipohyalinosis as a result of poorly controlled hypertension 1. This renders the vessel wall prone to rupture. The larger paramedian perforators are more commonly the culprit vessels 1.
Haemorrhage into the pons can of course also be secondary to underlying lesions including: