Arteriovenous malformation within the velum interpositum.

We present a case involving a 70-year-old Latina woman who experienced a sud-den onset of lightheadedness, diplopia, vertigo, and loss of balance. Imaging studies revealed a right thalamic intracerebral haemorrhage that obstructed the velum interpositum. Following unsuccessful embolisation, the thalamic region was surgically resected. Histopathological and immunohistochemical analyses of the resected brain tissue demonstrated abnormal blood vessels permeating through excessively cellular brain parenchyma, raising significant concern for a glial neoplasm. This case also illustrates a rare occurrence of an arteriovenous malformation within the velum interpositum, which, when acutely filled with blood, can expand the cavum and clinically present as a sudden onset of headache and vertigo.