Differential Diagnosis for Multiple Ill-Defined Hypodensities in the Subcortical Deep White Matter

Single Most Likely Diagnosis

• Small Vessel Disease: This is the most likely diagnosis due to the presence of multiple ill-defined hypodensities in the subcortical deep white matter, which is a common finding in small vessel disease, particularly in elderly patients or those with risk factors such as hypertension, diabetes, and smoking.

Other Likely Diagnoses

• Multiple Sclerosis: Although less likely than small vessel disease, multiple sclerosis (MS) can present with similar imaging findings, especially in younger patients. The presence of periventricular lesions and lesions in the corpus callosum would support this diagnosis.
• Chronic Microvascular Ischemic Changes: These changes can occur due to chronic ischemia and can present with similar imaging findings, often in patients with a history of vascular risk factors.
• Leukoaraiosis: This term refers to the appearance of white matter changes on imaging, often associated with aging, hypertension, and small vessel disease. It can present with similar imaging findings.

Do Not Miss Diagnoses

• Progressive Multifocal Leukoencephalopathy (PML): Although rare, PML is a potentially fatal condition that can present with similar imaging findings, particularly in immunocompromised patients. It is essential to consider this diagnosis to initiate prompt treatment.
• CNS Lymphoma: Primary CNS lymphoma can present with white matter lesions, and it is crucial to consider this diagnosis, especially in immunocompromised patients or those with a history of cancer.
• Vasculitis: Central nervous system vasculitis can present with similar imaging findings, and it is essential to consider this diagnosis, as it requires prompt treatment to prevent further damage.

Rare Diagnoses

• CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy): This is a rare genetic disorder that presents with similar imaging findings, often in younger patients without traditional vascular risk factors.
• MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes) Syndrome: This is a rare mitochondrial disorder that can present with similar imaging findings, often in younger patients with a history of seizures, headaches, and stroke-like episodes.
• Susac Syndrome: This is a rare condition characterized by microangiopathic changes in the brain, retina, and cochlea, which can present with similar imaging findings, often in young women.