Central nervous system (CNS) cavernous malformations (CMs) are developmental malformations of the vascular bed with a highly variable clinical course due to their dynamic nature. We present one case of 'de novo' brainstem cavernous malformation after radiation therapy adding to the increasing number of reported cases in the medical literature, and the case of a pregnant patient with symptomatic intracranial hemorrhage related to brainstem CMs to illustrate the complex nature in management of these patients, followed by a review of clinical and radiographic characteristics. CMs account for 8-15% of all intracranial and intraspinal vascular malformations. Although traditionally thought to be congenital in origin, CMs may present as acquired lesions particularly after intracranial radiation therapy. Clinical manifestations are protean and surgical treatment should be considered for patients with progressive neurologic deficits.