Supracerebellar Approach to Radiation-Induced Giant Capillary Telangiectasia Within Juvenile Pilocytic Astrocytoma of Upper Brainstem.

Radiation-induced telangiectasia of the central nervous system has been described predominantly in children, with up to 20% of patients affected after 3-41 years of radiotherapy. We present the case of a 45-year-old male with a pontine pilocytic astrocytoma treated with standard-dose radiation for 6 weeks in 1993. He developed a 3-cm multicystic, hemorrhagic brainstem lesion but was asymptomatic. The lesion caused severe brainstem mass effect, compatible with cavernous malformation or capillary telangiectasia. It has been reported that cavernomas and capillary telangiectasias share a similar pathologic process. The patient was surgically treated with a supracerebellar infratentorial approach to diagnose the hemorrhagic component of the lesion and ensure there was no transformation of the pilocytic astrocytoma (Video 1). He was placed in a gravity-dependent supine position with the head flexed and turned to allow for natural relaxation of the cerebellum via gravity-a technique we previously described. Surgical treatment proceeded with a left suboccipital craniotomy to decompress the cyst and facilitate removal of the intraaxial lesion. We took care to avoid injuring the fourth and fifth cranial nerves and branches of the superior cerebellar artery. No further lesional tissue was seen in the resection cavity. Interestingly, the final pathologic diagnosis indicated a mix of both pilocytic astrocytoma and radiation-induced capillary telangiectasia. From the surgeon's perspective, capillary telangiectasias appear similar to cavernous malformations on gross inspection, so pathologic confirmation is essential. Postoperative imaging demonstrated total resection of the lesion. The patient was discharged on postoperative day 3 with no neurologic deficit.