2Frequency: JNA accounts for 0.05% of all head and neck tumors. Sex: JNA occurs exclusively in males.Age: range is 7-19 years. JNA is rare in patients older than 25 yearsEtiology: A hormonal theory has been suggested due to the lesion's occurrence in adolescent males.
3Pathophysiology:The tumor starts adjacent to the sphenopalatine foramen. Large tumors frequently are bilobed or dumbbell-shaped, with one portion of the tumor filling the nasopharynx and the other portion extending to the pterygopalatine fossa.
5Clinical: Symptoms:Nasal obstruction (80-90%):Epistaxis (45-60%):Headache (25%):Facial swelling (10-18%)Other symptoms include unilateral rhinorrhea, anosmia, hyposmia, rhinolalia, deafness, otalgia, swelling of the palate, and deformity of the cheek.
6Signs:Nasal mass (80%)Orbital mass (15%)Proptosis (10-15%)Other signs may include-Serous otitis due to eustachian tube blockage.-Zygomatic swelling and trismus denote spread of the tumor to the infratemporal fossa.
7Differentials:Other causes of nasal obstruction, (eg, nasal polyps, antrochoanal polyp, teratoma, encephalocele, dermoids, inverting papilloma, rhabdomyosarcoma, squamous cell carcinoma)Other causes of epistaxis, systemic or localOther causes of proptosis or orbital swelling
12Anatomy Anteriorly -- nasal cavity Posteriorly -- skull base and vertebral bodiesInferiorly -- oropharynx and soft palateLaterally --Eustachian tubes and toriFossa of Rosenmuller - most common location
14Anatomy Close association with skull base foramen Mucosa Epithelium - tissue of origin of NPCStratified squamous epitheliumPseudostratified columnar epitheliumSalivary, Lymphoid structures
15Epidemiology Chinese native (广东，广西。湖南，福建） > Chinese immigrant > North American nativeBoth genetic and environmental factorsGeneticHLA histocompatibility loci possible markers
16Epidemiology Environmental Viruses Nitrosamines - salted fish EBV- well documented viral “fingerprints” in tumor cells and also anti-EBV serologies with WHO type II and III NPCHPV - possible factor in WHO type I lesionsNitrosamines - salted fishOthers - chronic nasal infection, poor hygiene, poor ventilation
18Clinical Presentation Xerophthalmia - greater sup. petrosal nFacial pain - Trigeminal n.Diplopia - CN VIOphthalmoplegia - CN III, IV, and VIcavernous sinus or superior orbital fissureHorner’s syndrome - cervical sympatheticsCN’s IX, X, XI, XII - extensive skull base
19Clinical Presentation Nasopharyngeal examinationFossa of Rosenmuller most common location
20Distant spread - rare (<3%), lungs, liver, bones Regional spreadUsually ipsilateral first but bilateral not uncommonDistant spread - rare (<3%), lungs, liver, bones
21Radiological evaluation Contrast CT with bone and soft tissue windowsimaging tool of choice for NPCMRIsoft tissue involvement, recurrencesChest CT, bone scans