**5. Conclusion**

Aneurysmal bone cyst is a benign, nonneoplastic lesion that presents most frequently under the age of 20 years. The metaphysis of long bones is the usual site of origin. Although the involvement of the skull is rare (2.5–6% of such cases reported in the literature), the skull vault is more often the site than the skull base. Benign ABCs are locally destructive entities which may occasionally present to otolaryngologists, since they can involve the head and neck region. ABC should be suspected, if a cystic mass in nasal cavity that is rapidly growing with fluid-fluid level in CT scan is encountered.
