Nasophary ngeal carcinoma caused by -
Ans. is 'a' i.e., EBV Nasopharyngeal Carcinomao Nasopharyngeal carcinoma is a rare tumor arising from epithelium of the nasopharynx. Nasopharyngeal cancer is uncommon in India except in North East region where people are predominantly of Mongoloid origin. People in Southern china. Taiwan and Indonesia are more prone to this cancer. The maximum age incidence is in the fifth decade and the male: female ratio is 2:1. Squamous cell carcinoma in various grades of its differentiation or its variants as transitional cell carcinoma and lymphoepithelioma, is the most common (85%).Etiologyo Nasopharyngeal carcinoma is multi factorial in origin, the three risk factors areGenetic : Chinese have a higher genetic susceptibility to nasopharyngeal cancer. Even after migration to other countries they continue to have higher incidence.Viral: Epstein- Bar virus is closely associated with nasopharyngeal cancer. Specific viral markers are being developed to screen people in high incidence areas.Environmental: Air pollution, smoking of tobacco and opium, nitrosamines from dry salted fish, smoke from burning of incense and wood have all been incriminated.Origin and spreado The commonest site of origin of nasopharyngeal carcinoma is fossa of Rosenmuller in the lateral wall of nasopharynx.o Tumor can spread to following areasCranium through foramen lacerum & ovale - cranial nerves involvement (III, IV, V, VI); facial pain, and ophthalmic symptoms.Parapharangeal space - cranial nerves (IX, X, XI, XII) involvement. Homer's syndrome. Trismus (Pterygoid muscle).Retropharyngeal nodes - Neck pain & stiffnessEustachian tube - Serous OMNose and orbit - Obstruction, epistaxis, proptosisCervical nodes - Upper jugular and posterior triangle nodes enlargement.Distant metastasis - Lung, liver, boneMiddle ear - Rarely, tumor grows up the tube into the middle ear.
EBV
HPV
HSV
VZV
Tumors