NPC arises from nasopharynx

NPC arises from nasopharynx i.e Fosaa of Rosenmullar and nasopharynx is lined by ciliated columner epithelium… despite this why NPC is Squamous cell carcinoma?
Nasopharyngeal carcinoma (NPC) is indeed a type of cancer that typically arises from the nasopharynx, specifically from the epithelial lining of the nasopharynx. Although the nasopharynx is normally lined by ciliated columnar epithelium, NPC is predominantly classified as a squamous cell carcinoma. This apparent discrepancy can be explained by a few factors:

  1. Nasopharyngeal epithelial transformation: The development of NPC involves a transformation of the normal nasopharyngeal epithelium. Over time, chronic irritation, inflammation, and exposure to various environmental factors (such as Epstein-Barr virus infection and dietary factors) can lead to cellular changes. These changes result in the replacement of the ciliated columnar epithelium by a non-ciliated squamous epithelium, which is more prone to malignant transformation.
  2. Epithelial metaplasia: The chronic inflammation and irritation in the nasopharynx can induce a process called metaplasia, where one type of epithelium is replaced by another. In the case of NPC, the metaplastic transformation leads to the replacement of the ciliated columnar epithelium with a squamous epithelium.
  3. Epstein-Barr virus (EBV) association: NPC is strongly associated with Epstein-Barr virus infection, particularly the EBV subtype known as EBV-associated NPC. The presence of EBV in nasopharyngeal cells can contribute to the squamous differentiation of the nasopharyngeal epithelium, promoting the development of squamous cell carcinoma.

It’s important to note that while squamous cell carcinoma is the predominant histological type of NPC, other histological subtypes can also occur, such as undifferentiated (lymphoepithelioma-like) carcinoma and rare variants like basaloid squamous cell carcinoma.

In summary, the squamous cell differentiation observed in NPC is a result of the metaplastic transformation of the nasopharyngeal epithelium under the influence of various factors, including chronic inflammation, environmental exposures, and the association with Epstein-Barr virus infection.