Isolated cortical vein thrombosis with hemorrhagic infarction during the application of a transdermal estradiol patch: A case report.

Isolated cortical vein thrombosis (ICVT) is a rarer subtype of cerebral venous sinus thrombosis (CVST) that involves only the cortical veins without any thrombosis in the major cerebral veins or sinuses. Among the known causes of CVST are factors, such as being a young female or the use of hormonal preparations. This study presents a case of a 35-year-old female who underwent endometrial polyp removal 5 days before symptom onset and started using a transdermal estradiol patch. After 4 days of using the transdermal estradiol patch, the patient developed recurrent seizures and sustained sensory aphasia. The head computed tomography revealed hemorrhagic infarction. Given her young age and the use of hormonal therapy, CVST was suspected. However, the initial diagnosis with magnetic resonance imaging (MRI) was inconclusive, and no venous sinus thrombosis could be identified on additional cerebral angiography. Instead, stasis of venous flow in the temporal vein was noted. It was difficult to determine whether these findings were due to hemorrhage or ICVT. Upon re-evaluation with MRI, signal changes suggestive of thrombosis in a cortical vein in the parietal region, which is different from the stasis observed in cerebral angiography, led to the diagnosis of ICVT. This is the first study to link the use of transdermal estradiol patches to ICVT. In cases where ICVT leads to cerebral hemorrhage, cerebral angiography may not be useful. Instead, a comprehensive diagnosis should be made based on imaging findings from various MRI sequences and the patient's medical history.