Rhinology, 41, 235–240, 2003 * Received for publication: June 12, 2001; accepted: November 2, 2001 Juvenile nasopharyngeal angiofibroma: the routes of invasion* Luiz U. Sennes, Ossamu Butugan, Tanit G. Sanchez, Ricardo F. Bento, Domingos H. Tsuji Otolaryngology Department of the University of São Paulo School of Medicine, Brazil INTRODUCTION Although the juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor, its behavior is often aggressive. From its origin in the sphenopalatine foramen region, the tumor grows in all directions through multiple projections. However, these pro- jections have distinct rates of development. Some tumors show preference to grow laterally, while others toward a poste- rior, medial, anterior or superior direction. The explanation to this fact is still unknown. Another controversial characteristic is its tendency to grow through high resistance ways between the bones, instead of only occupying space. The best example is the invasion of the pterygopalatine fossa through the narrow pterygomaxillary fis- sure, which is considered the most important event to the tumor development (Weprin and Siemers, 1991). A similar question remains about its preference to invade the cranial fossa by a parasellar route (lateral to the sphenoid sinus) rather than through the sphenoid itself, which represents an easier route. Also, some authors believe that the tumor aggressiveness is related to the patient’s age, observing that both intracranial and infratemporal invasion usually occur in younger patients (Jafek et al., 1979). However, others did not find this correla- tion and consider these extensions as a result of anatomic peculiarities (Bremer et al., 1986). The aim of this study is to analyze the preferential direction and routes of JNA growth, as well as its correlation with the patient’s age. MATERIAL AND METHODS Thirty-three untreated patients with histological diagnosis of JNA were studied in the Otolaryngology Department of the University of São Paulo. All patients were white males and the age ranged from 9 to 25 years (mean 15.66; median 16 years). The extension of the tumor was evaluated on CT scans (iodine-contrasted coronal and axial 5mm cuts) and they were classified according to Sessions et al. (1981). The route of inva- sion of each craniofacial site was deduced by the dislocation SUMMARY The juvenile nasopharyngeal angiofibroma has a characteristic growth in all directions from its origin. However, the extensions of the tumor seem to be independent, each one with dis- tinct behavior. The aim of this study is to analyze the preferential direction and routes of JNA growth, as well as its correlation with the patient’s age. We analyzed 33 patients with- out any previous treatment, attempting to the extension and routes of tumor’s growth (CT scan), and its correlation with the patient’s age. The sphenopalatine foramen region was affected in all cases. From this point, a growth towards several routes with a different rhythm was noted, determining variable configurations to the tumor. The lateral and superior growths were the most frequent. The expansion into the pterygopalatine fossa was very fre- quent and could involve important anatomical structures, determining higher morbidity. Three sites were invaded through more than one route: pterygoid fossa, middle cranial fossa and maxillary sinus. There was no significant correlation between invasion route and patient’s age. However, considering the age, there was a concomitance between tumor devel- opment and facial growth by “displacement”. We discuss this condition, suggesting an expla- nation to the tumor invasion and expansion inside the pterygopalatine fossa. Key words: angiofibroma, skull base tumors, facial growth, pterygopalatine fossa, nasopha- ryngeal tumors Presented at the XIV Congress of the European Rhinology Society and the XX ISIAN, Vienna, Austria, July 28 – August 1, 1998. Recipient of an Award of Excellence (3rd place).