Spread and metastasis of nasopharyngeal carcinoma

The spread and metastasis of nasopharyngeal carcinoma include:

1. Direct spread

(1) Spread downward: along the soft palate, tonsils and root of the tongue to the epiglottis and larynx.

(2) Spread forward: It can reach the posterior part of the nasal cavity and the ethmoid sinus, and then pass through the cribriform plate to the anterior cranial fossa and maxillary sinus.

(3) Spread upward: to the base of the skull, invade beneath the dura mater, and may also invade the skull.

(4) Spread outward: Invading the parapharyngeal space, infratemporal fossa, posterior area of ​​the styloid process, and posterior cranial nerves.

(5) Spreading backwards: From the posterior wall of the nasopharynx, it invades the upper cervical vertebrae and, to a lesser extent, the cervical spinal cord.

(6) Spread to both sides: Invasion of the Eustachian tube to the inner ear and middle ear.

During the process of nasopharyngeal carcinoma infiltrating the periphery and the brain, the trigeminal nerve, abducens nerve, glossopharyngeal nerve, and hypoglossal nerve are more frequently affected, while the olfactory nerve, facial nerve, and auditory nerve are less commonly affected.

2. Lymph node metastasis is the most important metastatic pathway and site. Moreover, metastasis occurs early and has a high incidence rate. About 40% of patients have initial symptoms, and 60% to 80% of patients have cervical lymph node metastasis when they seek medical treatment. Cervical lymph nodes account for about 1/3 of the body's lymph nodes, especially deep lymph nodes, which are closely related to tumor metastasis. Metastatic lymph nodes are often multiple, unequally sized, hard masses. Generally, they grow from small to large as the disease progresses, and their number increases. They gradually merge into huge masses, and their mobility is gradually limited. Usually, the metastasis is from the upper neck to the lower neck. About half of the patients have metastasis on both sides of the neck, and preauricular lymph node metastasis is less common.

3. Distant metastasis The rate of distant metastasis of nasopharyngeal carcinoma is relatively high, which is obviously related to whether the primary tumor invades outside the nasopharynx, whether the cervical lymph nodes have metastasized, as well as the size and location. The rate of distant metastasis is higher when the tumor invades the oropharynx or nasal cavity. The metastatic site can be single or multiple. Common sites of distant metastasis are bones, lungs, and liver. Bone metastasis is more common in the spine, pelvis, and limbs. Metastasis to the thoracic cavity, abdominal cavity, mediastinal lymph nodes, inguinal lymph nodes, etc. can also occur. Distant metastasis is mostly a manifestation of the late stage and is the result of hematogenous metastasis. The head and neck have rich blood circulation. If there is cervical lymph node metastasis, tumor cells have many opportunities to invade the large veins. Therefore, hematogenous metastasis is prone to occur, which may be one of the reasons for the rapid development and poor prognosis of nasopharyngeal carcinoma.