Role of Volumetric Modulated Arc Therapy in a Rare Case of Aneurysmal Bone Cyst in Skull Base

A BSTRACT An aneurysmal bone cyst (ABC) is primarily a vascular tumor that causes partial vascular occlusion, leading to bony expansion. It is rare and attributes to only 1%–2% of primary bone tumors. Usually, it is found in long bones, with only 2% tumors in the head and neck region. Pain and slow-growing swelling are the most common presentations while other symptoms are attributed to pressure symptoms due to swelling. Radiologically, there are fluid–fluid interfaces and multiple cysts within ABCs. Biopsy is the mainstay of diagnosis. The only established and standard treatment is surgery. However, ABCs show a high rate of local recurrence even after complete resection. Getting a clear margin is difficult in anatomically inaccessible areas. Selective arterial embolization in large ABCs improves surgical outcome. There is a long data since the era of orthovoltage radiotherapy (RT) regarding the use of RT in ABCs for local control. Still, there is no proper RT guideline in ABC. Here, we are presenting a rare case of ABC of skull base in a 27-year-old man treated with volumetric modulated arc therapy.