Nasopharyngeal carcinoma

Nasopharynx cancer or nasopharyngeal carcinoma (NPC) is the most common cancer which is formed in the nasopharynx, most commonly in the postero-lateral nasopharynx or pharyngeal recess or 'Fossa of Rosenmüller' accounting for 50% cases. 
NPC happens in children and adults. NPC differs significantly from other cancers of the head and neck in its occurrence, causes, clinical behavior, and treatment. 
It is vastly more common in certain regions of East Asia and Africa than elsewhere, with viral, dietary and genetic factors implicated in its causation. It is most common in males. It is a squamous cell carcinoma or an undifferentiated type. Squamous epithelial cells are a flat type of cell found in the skin and the membranes that line some body cavities. 
Differentiation means how different the cancer cells are from normal cells. "Undifferentiated cells" are cells that do not have their mature features or functions.