336P - Case report of the effective use of BRAF inhibitor vemurafenib in a patient with relapse of pleomorphic xanthoastrocytoma

Abstract

Pleomorphic xanthoastrocytoma is a rare tumor of the brain. It is approximately 1% of the astocytomas of the brain. In some cases, the tumor is well-demarcated and slow-growing with a favorable prognosis. At the same time reported cases of its malignant transformation with a poor prognosis. Most often this tumor occurs in a young age and manifest with epileptic syndrome. The main treatment is surgical. According to the literature, 30-40% of patients with pleomorphic xanthoastrocytoma detected mutation of V600E BRAF was. The patient 25 years old in January 2011 revealed a tumor of the left occipital lobe of the brain. 22 Jan 2011 completed the removal of a brain tumor. Morphologically diagnosed as a pleomorphic xanthoastrocytoma with signs of anaplasia grade 3, Ki-67 – 15%. In the postoperative, in February-April 2012, conducted a course of radiation therapy to the left occipital lobe of the brain with total focal dose 60 Gy. In September 2014 after 2 years and 8 months after the operation revealed a relapse of a brain tumor. 25 Sep 2014 made the removal of the recurrence of a brain tumor. Morphologically diagnosed as a pleomorphic xanthoastrocytoma with signs of anaplasia grade 4, Ki-67 > 20%. Carried out a genetic examination of the tumor. Revealed no methylation of the MGMT gene in the tumor. The identified mutation V600E BRAF in the tumor. In December 2014 marked the progression of the disease. Revealed continued tumor growth in the brain. The size of the recurrent tumor 4 x 3 cm. From December 2014 we started the targeted therapy with Vemurafenib. Achieved partial regression of the tumor in the brain. The size of residual tumors currently, less than 1 cm. Therapy with Vemurafenib lasts 1 year and 6 months. Thus, the presence of the V600E BRAF mutation is another target for effective treatment of recurrences of pleomorphic xanthoastrocytoma. Further studies are needed for the study of BRAF inhibitors in patients with pleomorphic xanthoastrocytoma.