Nasopharyngeal cancer is a rare type of cancer that occurs in the nasopharynx, the upper part of the throat behind the nose. It arises when the cells in the nasopharyngeal lining grow abnormally and form malignant tumors. Nasopharyngeal cancer can be caused by various factors, including genetic predisposition, exposure to certain viruses such as Epstein-Barr virus, and environmental factors.