The hypopharynx is the part of the throat (pharynx
) that lies beside and behind the larynx. The hypopharynx is the entrance into the esophagus. Food goes from the mouth and through the hypopharynx and esophagus, where it then passes into the stomach. The structure of the hypopharynx makes sure that food goes around the larynx and into the esophagus.
Squamous Cell Carcinomas
Almost all cancers in the hypopharynx develop from the thin, flat cells called squamous cells, which are in the epithelium, the inner layer lining the hypopharynx. Cancer beginning in this layer of cells is called squamous cell carcinoma
or squamous cell cancer
Most squamous cell cancers of the hypopharynx begin as pre-cancerous conditions called dysplasia
. Most of the time, dysplasia doesn't turn into actual cancer. It often goes away without any treatment.
Some cases of dysplasia will progress into a condition called carcinoma in situ
. In this stage, cancer cells are only seen in the epithelium lining. They have not grown into deeper layers or spread to other parts of the body. It is the earliest form of cancer.
Other rare types of cancer can also start in the hypopharynx.
Minor Salivary Gland Cancers:
Some areas of the hypopharynx have tiny glands known as minor salivary glands
beneath the lining layer. These glands produce mucus and saliva to lubricate and moisten the area.
The shape of the hypopharynx depends on a framework of connective tissues and cartilage. Cancers like chondrosarcomas
or synovial sarcomas
can develop from connective tissues of the hypopharynx. This is extremely rare.
Although, these cancers usually start in the skin, in rare cases they can start on inner (mucosal
) surfaces of the body such as the hypopharynx.