After diagnosing a patient with nasopharyngeal cancer, a doctor will need to determine what type of cancer it is, the grade of the tumor, and the stage of the cancer. Doctors often establish a preliminary disease stage based on physical exam as well as findings on imaging that help to identify the spread of disease.
Type
Only after a pathologist analyzes some cells or actual pieces of tissue from the lesion will a doctor be able to tell if a patient has nasopharyngeal (NPC) cancer. Below are the different types of NPC. They all start from epithelial cells that line the nasopharynx, but they differ depending on what the cells look like under the microscope. There are three main types of nasopharyngeal cancer defined by the World Health Organization (WHO): keratinizing squamous cell carcinoma, non-keratinizing carcinoma (subdivided into differentiated and undifferentiated), and basaloid squamous cell carcinoma.
Keratinizing squamous cell carcinoma (WHO type I)
These are similar to other squamous cell carcinomas and are typically well or moderately differentiated in terms of grade.
Non-keratinizing carcinoma
Differentiated (WHO type II)
These can look like squamous cell carcinomas in other non-head-and-neck sites. These can vary quite a bit in grade.
Undifferentiated (WHO type III)
This is the most common type of NPC and the most strongly associated with EBV. It also carries the best prognosis of all the subtypes.
Basaloid Squamous Cell Carcinoma
This subtype is less common, but has a notably aggressive behavior.
Less common types of nasopharyngeal cancer
- Sarcomas such as chondrosarcoma, liposarcoma and synovial sarcoma.
- Malignant fibrous histiocytoma.
- Peripheral Neuroectodermal Tumor (PNET).
- Cancer spread from another site (metastasis).
Other possible diagnoses
- Salivary gland cancers: There are minor salivary glands located under the lining of the throat. This is why cancers that we typically see in salivary glands can arise in this region and they include diagnoses such as mucoepidermoid carcinomas, adenocarcinomas and adenoid cystic carcinomas, to name a few. See the Salivary Gland Cancer for more information.
- Lymphoma: The throat is lined with lymphoid cells. Some major sites of lymphoid tissue include the adenoids in the nasopharynx (part of the throat behind the nose) and tonsils in the oropharynx. This is why lymphoma might appear as a lump in the throat area.
- Mucosal melanoma: These cancers come from skin cells that give skin its color. In rare cases, melanoma can be found in the lining of the mouth, nose and/or throat.
