Ischemic Stroke: This is the most common cause of a stroke in the putamen, which is a part of the basal ganglia. The putamen is a common site for ischemic strokes due to its blood supply from the lenticulostriate arteries, which are prone to atherosclerosis and small vessel disease.

Hemorrhagic Stroke: Although less common than ischemic strokes, hemorrhagic strokes can also occur in the putamen, often due to hypertension causing rupture of small vessels.
Lacunar Infarct: Given the location in the putamen, a lacunar infarct (a small infarct in the deeper parts of the brain) is a possibility, typically resulting from occlusion of the penetrating arteries.
Cerebral Vasculitis: Inflammation of the blood vessels in the brain can lead to stroke-like symptoms and may affect the putamen, though it is less common.

Venous Thrombosis: Although less common than arterial strokes, cerebral venous thrombosis can cause stroke-like symptoms and should not be missed due to its potential for severe outcomes if not treated promptly.
Malignancy (e.g., Brain Metastasis): A mass lesion in the putamen could mimic a stroke and needs to be considered, especially in patients with a known history of cancer.
Infections (e.g., Brain Abscess): An abscess in the brain can present with focal neurological deficits similar to a stroke and is critical to diagnose due to the need for urgent treatment.

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS): A rare mitochondrial disorder that can cause stroke-like episodes, including in the putamen.
CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy): A rare hereditary condition leading to subcortical strokes and dementia.
Fabry Disease: A genetic disorder that can lead to stroke due to vascular dysfunction, though it is rare and typically presents with other systemic symptoms.