Introduction: Giant cell tumor is a locally aggressive benign primitive bone tumor, the vertebral location is exceptional, and rarely associates with an aneurysmal cyst, we report a case of vertebral giant cell tumor, colonized by an aneurysmal cyst revealed by a Pancoast syndrome. Case presentation: We report the case of a 19 years old female patient, present since 6 months a symptom of horner syndrome, with pain located on the shoulder and the inter scapula-vertebral space, inflammation blood test were negative, radiological assessment showed a lytic lesion process centered on D1 extends into spine canal and inside the thorax, Biopsy: Giant cell tumor, colonized by an aneurysmal cyst. Conclusion: The giant cell tumor with vertebral location is a very aggressive tumor; IT can be associated with an aneurysmal cyst responsible for tumor hypervascularization, necessitating preoperative embolization.