Rhinology, 42, 164-166, 2004 *Received for publication: December 12, 2003; accepted: February 12, 2004 INTRODUCTION Although aneurysmal bone cyst (ABC) is a non-neoplassic lesion, it expands from the affected bone and destroys the sur- rounding tissues. Only 2% of all aneurysmal bone cysts are found in the head and neck area, being mandible the most fre- quent site and usually affecting young patients. ABC was first described in 1942 by Jaffe and Lichtenstein (1942). There have been occasional reports of sphenoid (Cansiz et al., 2002) and maxillary (Suzuki et al., 2001) sinus involvement but primary ethmoid ABC is extremely rare, with only eight reported cases (Odenthal, 1967; Baker et al., 1982; Jordan et al., 1983; Patel et al., 1993; Zielnik et al., 1995; Citardi et al., 1996; Winnepenninckx et al., 2001; Hrischhikesh et al., 2002), four of them with orbital extension (Odenthal, 1967; Jordan et al., 1983; Patel et al., 1993; Citardi et al., 1996), and one in the lachrymal bone (Citardi et al., 1996). Surgery is the therapy of choice for ABC. Radiation therapy alone or combined with chemotherapy has not been effective in the treatment. Radiation therapy carries the hazard of radia- tion-induced sarcoma (Bernier and Bhaskar, 1958). Another effective treatment reported is the cryosurgery, especially in ABC of the jaw (El Deeb et al., 1980). Due to the rarity of these tumors we also report all the pub- lished ethmoidal ABC in order to contribute to the characteri- zation of the clinicopathological features and to the manage- ment of these neoplasms. CASE REPORT A 62-year-old-female with no prior history of trauma or sinus disease consulted for a 2 months history of right-sided nasal pain with rhinorrhea and epiphora without nasal obstruction. She also presented right ocular pain that increased with lateral eye movement but without proptosis or limitation in ocular motility. Pupillary and funduscopic examination were normal. A follicular non-Hodkin lymphoma was diagnosed 2 years ear- lier by right cervical adenopathy exeresis. Currently, the Aneurysmal bone cyst is a benign, vascular, variable growing and expansive lesion that can occur in any part of the skeletal system, but mainly in long bones and vertebrae. We present a case of orbitoethmoid aneurysmal bone cyst in a 62-year-old female presenting epiphora. Nasal endoscopy was normal. Sinus CT scan revealed an expansive mass in the right ethmoid sinus extending and destroying the right lamina papiracea. The tumor was completely resected through paralateral rhinotomy. Histological analysis showed fibrous septa containing multin- ucleated giant cells and bone tissue surrounding blood vessel lumens, bordered by endothelial cells. These findings are characteristic of aneurysmal bone cysts. After 30 months of postoper- ative follow-up the patient remains disease-free and asymptomatic. Key words: aneurysmal bone cyst, paranasal sinuses, ethmoid sinus SUMMARY Orbitoethmoid aneurysmal bone cyst. Case report and literature review* Jose Maria Guilemany 1 , Isam Alobid 1 , Jose Luis Blanch 1 , Ferran Ballesteros 1 , Llucia Alós 2 , Joaquim Mullol 1 1 Department of Otorhinolaryngology, Hospital clínic, Barcelona, Spain 2 Department of Pathology, Hospital clínic, Barcelona, Spain CASE REPORT Figure 1. Coronal CT shows the lesion in the right nasal cavity with lytic and expansive characteristics, surrounded by a thin rim of bone.