Internal Cerebral Vein Thrombus Mimicking Thalamic Neoplasm in a Child with Down Syndrome

Thalamic strokes are uncommon in children and often arise from underlying conditions such as coagulopathy. Their clinical and radiological resemblance to neoplasms - with shared symptoms and overlapping MRI features - makes accurate diagnosis particularly challenging.

A 2-year-old boy with trisomy 21 (Down syndrome) presented with 5 days of altered mentation and fussiness, nausea, vomiting, and seizures. CT head demonstrated a right thalamic edematous lesion. MRI showed a lesion with imaging features suggestive of a thalamic neoplasm that was ultimately found to be an infarct secondary to right internal cerebral vein thrombus. The patient was treated with heparin and returned to his clinical baseline.

Given their predisposition to coagulopathy, patients with Down syndrome require meticulous imaging evaluation. CT venogram can be an essential part of workup for this patient population.