Nasopharyngeal carcinoma is a malignant tumor that occurs in the top and side walls of the nasopharynx. Nasopharyngeal carcinoma spreads in two ways.
(i) Invasion of the skull base and the resulting invasion into the skull, resulting in bone destruction, brain nerve invasion or compression, with the third, fourth, fifth and sixth pairs of brain nerves being the most common.
Extracranial extension can directly invade adjacent sinuses such as nasopharynx, oropharynx, parapharyngeal tissue, pterygopalatine fossa, and even the orbit. The metastasis of nasopharyngeal cancer is usually lymphatic metastasis, which can reach deep cervical lymph nodes, middle cervical, subcervical and supraclavicular lymph nodes. Zhang Jiexia, Department of Respiratory Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China Patients with early-stage nasopharyngeal carcinoma who are commonly detected are generally asymptomatic, except for very few who occasionally have tinnitus and runny blood. Symptoms and signs of nasopharyngeal cancer patients include nasal congestion, runny blood, otitis media, tinnitus, vision loss, eye abduction movement disorder, diplopia, migraine, toothache, fever, hoarseness, enlarged lymph nodes in the neck, and corresponding symptoms caused by distant metastasis.
Genetic factors: Nasopharyngeal carcinoma is mainly found in the yellow race. The southern provinces of China (Guangdong, Guangxi, Hunan, Fujian) and some countries in Southeast Asia are the regions with the highest incidence of nasopharyngeal cancer in the world. Guangdong Province has the highest incidence rate in Guangzhou, Foshan, Zhaoqing and other areas, with 18-27 people suffering from this disease per 100,000 men, while women account for 8-9 people. Even if people from high incidence areas move to distant places, such as the northeast, their descendants still maintain a high tendency to develop the disease, which illustrates the obvious racial sensitivity of the occurrence of nasopharyngeal cancer. In addition, a tendency of family aggregation can be found in both high and low incidence areas. For example, a typical example was found in the census, where 10 out of 49 people in a family of three generations had cancer, 9 of which were nasopharyngeal carcinoma. It can be concluded that genetic factors play an important role in the etiology of nasopharyngeal cancer.
Environmental carcinogenic factors: Many investigation reports and experimental results show that the occurrence of nasopharyngeal carcinoma is related to the living environment of residents in high incidence areas and to some carcinogenic substances that they are exposed to in clothing, food, housing and transportation. For example, many residents in high incidence areas like to eat salted fish since childhood, which contains more nitrosamines; smoke in patients’ homes contains a lot of aromatic polycyclic hydrocarbons; in addition, air, water, food and even patients’ hair in high incidence areas contain more trace elements of nickel, etc. These substances are considered to have carcinogenic effects. There are also different views on the relationship between nasopharyngeal cancer and environmental carcinogenic factors.
Treatment for nasopharyngeal cancer includes radiation therapy, surgical treatment and chemotherapy, as well as immunotherapy and Chinese medicine. Nasopharyngeal cancer has certain sensitivity to radiation, and the primary lesion of nasopharyngeal cancer and cervical lymph node drainage area can be included in the irradiation field. Chemical anticancer drugs have certain recent efficacy in the treatment of nasopharyngeal carcinoma, and high-dose DDP and 5-Fu can achieve a 90% remission rate. However, integrated treatment with radiation is also needed after applying chemotherapy.
I. Radiation therapy.
Radiotherapy is recognized as the first choice for nasopharyngeal carcinoma, and in 1979, the National Conference on Nasopharyngeal Carcinoma proposed that radiotherapy should be the main treatment for stage I nasopharyngeal cancer. Radiation therapy for nasopharyngeal cancer can be divided into radical radiation therapy and palliative radiation therapy.
Contraindications for radiation therapy are: ① Karnofski classification below 60; ② extensive distant metastasis; ③ radioactive cerebrospinal cord injury; ④ other diseases such as infectious disease or psychiatric disease have not been controlled.
Radiation therapy for nasopharyngeal cancer can kill tumor cells, but normal tissues or organs are inevitably irradiated and produce radiation reactions. The radiation reaction is closely related to the dose, the scope of irradiation, the number of courses of irradiation, and the degree of tolerance of normal tissues or organs.
Radiation reactions.
(1) Systemic radiation reactions: including weakness, dizziness, loss of appetite, nausea, vomiting, tastelessness or change of taste in the mouth, insomnia or drowsiness, etc. Although the degree varies, it can generally be overcome by symptomatic treatment to complete the course of radiation therapy.
(2) Mucosal reaction: Mucous membrane in the oropharynx, nasopharynx, nasal cavity and paranasal sinuses may become edematous or congested after 40Gy radiation, with increased exudation, which may cause dotted or lamellar white film when serious. During the irradiation process, there is often pain in the throat, difficulty in eating, nasal congestion and so on. In severe cases, irradiation should be suspended, rested appropriately, and treated after the reaction has subsided. Generally, it can be gradually absorbed and faded 1 year after radiotherapy, but there are a few cases that still exist more than 10 years after radiotherapy.
(3) Salivary gland radiation reaction: saliva secretion is significantly reduced, patients have dry mouth and difficulty in eating dry food.
(4) Radiation reaction of skin and subcutaneous tissue: erythema, hyperpigmentation, hair loss and dry desquamation generally appear on the skin in the irradiated area.
(5) Late radiation reaction of radiation therapy: skin and subcutaneous tissue atrophy, skin thinning, capillary dilation, hypopigmentation, etc. are often seen on the face and neck.
(6) Difficulty in opening the mouth: Masticatory muscles and temporomandibular joints may be irradiated to different degrees, causing difficulty in opening the mouth.
7) Radioactive dental caries and radioactive osteonecrosis of the jaw.
8) Radiation skin and subcutaneous tissue dermatitis.
9）Radioactive otitis media.
10）Radioactive brain and spinal cord injury.
II. Surgical treatment.
Applicable objects.
1）Pathological type of highly differentiated squamous carcinoma or adenocarcinoma and other carcinomas insensitive to radiation, with lesions confined to the posterior or anterior wall of the apex, and no contraindications to surgery in the whole body can be considered for resection of primary lesions. Patients with stage II, III and IV are not suitable for surgical treatment.
(2) For patients with residual or recurrent lesions in the nasopharynx or neck after radiation therapy, such as those confined to the posterior or anterior wall of the nasopharynx, without skull base bone destruction, in good general condition, and those who have recently undergone radiotherapy and should not be treated with radiotherapy, resection of the lesions can be considered.
(3) If there is residue or recurrence in the neck, lymph node removal surgery in the neck can be considered if the scope is limited and active.
If there are residual lymph nodes in the neck after radiotherapy for nasopharyngeal carcinoma, it is advisable to operate early, and timely treatment within 3-6 months after radiotherapy will lead to better prognosis.
III. Chemotherapy.
More than 95% of nasopharyngeal carcinoma belongs to low differentiated carcinoma and undifferentiated carcinoma type, with high malignancy, fast growth and easy to appear lymph node or blood channel metastasis. When nasopharyngeal carcinoma is diagnosed, 75% of the patients already belong to stage III and IV. The later the stage of the disease, the more chances of distant metastasis and the worse the prognosis. Radiotherapy is a local treatment method, which cannot prevent distant metastasis. Therefore, combined application of chemicals or combination of several drugs may shrink the tumor or eliminate microscopic lesions and improve the treatment effect. Main methods.
(1) Combination chemotherapy regimens.
(1) CF program: cyclophosphamide and 5-fluorouracil are both broad-spectrum anti-cancer drugs, which have certain efficacy on nasopharyngeal cancer.
(2) PF regimen: Combined application of cis-chloroplatinum and 5-fluorouracil has good efficacy in nasopharyngeal carcinoma with rapid effect, but the disadvantage is short remission period. It can be used to shrink the tumor before radiotherapy, or for patients treated with chemotherapy alone.
3) PFA regimen: cis-chloroplatinum and 5-fluorouracil, hydroxytalinen, and adriamycin. It has the effect of shrinking tumor significantly.
(4) CBF regimen: mainly using cyclophosphamide, scramblomycin and 5-fluorouracil.
(2) Combined chemotherapy and radiation therapy: the treatment effect is better and the 5-year survival rate is higher.
【Diagnosis】.
In addition to noting the above clinical manifestations, the following examinations should be done.
(a) Anterior nasal aperture microscopy After convergence of nasal mucosa, the posterior nostril and nasopharynx can be peered through anterior nasal aperture microscopy, which can detect the cancer invading or adjacent to the nostril.
(2) Indirect nasopharyngoscopy is a simple and practical method. All walls of nasopharynx should be examined in turn, paying attention to the posterior wall of nasopharyngeal apex and both sides of pharyngeal fossa, and the corresponding parts of both sides should be observed in comparison.
(C) fiberoptic nasopharyngoscopy Fiberoptic nasopharyngoscopy can be performed first with 1% ephedrine solution to astringent nasal mucosa to expand the nasal passage. Then use 1% dicaine solution to surface anesthetize the nasal tract, and then insert the fiberoptic mirror from the nasal cavity, observe on one side and push forward to the nasopharyngeal cavity. This method is simple and the mirror is well fixed, but the posterior nostril and the anterior parietal wall are not satisfactorily observed.
(iv) Neck biopsy A biopsy of the neck mass can be performed in cases where the nasopharyngeal biopsy has failed to confirm the diagnosis. Generally, it can be performed under local anesthesia, and the earliest hard and solid lymph nodes should be selected, and the whole lymph nodes should be removed with the envelope. If it is difficult to remove the biopsy, a wedge-shaped biopsy can be made at the mass, and the tissue must be cut to a certain depth and not squeezed. The surgical field should not be sutured too tightly at the end of the operation.
(E) Fine needle aspiration This is a simple, easy, safe and efficient method for tumor diagnosis, which is more popular in recent years. For those who are suspected to have lymph node metastasis in the neck, fine needle aspiration can be used first to obtain cells. The specific methods are as follows.
1.Nasopharyngeal swelling puncture: Use a 7-gauge long needle attached to a syringe. After the oropharynx is anesthetized, the needle is inserted into the tumor parenchyma under indirect nasopharyngoscopy, and the syringe is extracted to make negative pressure, which can be moved back and forth twice in the tumor.
2.Fine needle puncture of neck mass: Use No.7 or No.9 needle attached to 10m1 syringe. After local skin disinfection, select the puncture site, enter the needle along the long axis of the tumor, aspirate the syringe and make the needle move back and forth within the mass 2 to 3 times, and remove the aspirate for cytologic or pathologic examination.
(vi) EBV serologic testing Currently, it is commonly used to detect the IgA/VCA and IgA/EA antibody titers of EBV by immunoenzymatic assay. The former is more sensitive and less accurate, while the latter is the opposite. Therefore, simultaneous testing of both antibodies is recommended for suspected nasopharyngeal carcinoma, which is helpful for early diagnosis. For cases with IgA/VCA titer ≥1:40 and/or IgA/EA titer ≥1:5, even if no abnormality is seen in the nasopharynx, exfoliated cells or biopsy should be taken from the site of nasopharyngeal cancer. If the diagnosis is still not confirmed for a while, regular follow-up should be performed, and multiple biopsies should be performed if necessary.
(VII) Lateral nasopharyngeal radiographs, skull base radiographs and CT examination Lateral nasopharyngeal radiographs and skull base radiographs should be routinely taken for each patient. In case of suspected invasion of paranasal sinuses, middle ear or other parts, corresponding radiographic examination should be done at the same time. CT scans should be performed if available to understand the local extension, especially the extent of infiltration in the parapharyngeal space. This is extremely important for determining clinical staging and developing treatment plans.
(H) B-mode ultrasonography B-mode ultrasonography has been widely used in the diagnosis and treatment of nasopharyngeal cancer, which is simple, non-invasive and readily accepted by patients. In cases of nasopharyngeal carcinoma, it is mainly used for examination of liver, neck, retroperitoneum and pelvic lymph nodes to understand whether there is liver metastasis and lymph node density, whether there is cystic, etc.
(ix) Magnetic resonance imaging examination Because magnetic resonance imaging (MRl) can clearly show all levels of the skull, brain sulcus, brain gyrus, gray matter, white matter and brain ventricles, cerebrospinal fluid ducts, blood vessels, etc., the SE method to display T1 and T2 extended high-intensity images can diagnose nasopharyngeal carcinoma, upper frontal sinus carcinoma, etc., and show the relationship between tumor and surrounding tissue.
【Treatment measures
(I) Radiation therapy Radiation therapy has been the first choice for the treatment of nasopharyngeal carcinoma. The reason is that most nasopharyngeal cancers are low differentiated cancers with high sensitivity to radiation, and the primary focus and lymphatic drainage area of the neck are easily included in the irradiation field. Since the 1940s, deep x-ray radiotherapy for nasopharyngeal cancer has been carried out in China, and from the 1950s to 1960s, 60Co external radiation radiotherapy has been carried out, and the combined large field irradiation of nasopharynx and neck has been changed to small field irradiation, which has reduced radiotherapy reactions and improved survival rate. At present, the most effective and sure method is to use 60Co teletherapy machine.
(1) Indications and contraindications of radiotherapy for nasopharyngeal cancer (1) Indications for radical radiotherapy: (1) those with moderate or above general condition; (2) those without obvious bone destruction at the skull base; (3) those with no or only mild to moderate infiltration at the nasopharyngeal parietal on CT or MRI film; (4) those with maximum diameter of cervical lymph nodes less than 8cm, active, not yet reaching the supraclavicular fossa; (5) those without distant organ metastasis.
(2) Indications for palliative radiotherapy: ① KS grading of 60 or more; ② severe headache, nasopharynx with more than moderate bleeding; ③ those with single distant metastasis or cervical lymph node metastasis greater than 10 cm; after palliative radiation, if the general condition improves, symptoms disappear and distant metastases can be controlled, the treatment can be changed to radical radiation. (3) Contraindications to radiation therapy: ① KS grading below 60 points; ② extensive distant metastases; ③ combined with acute infectious diseases; ④ radioactive cerebrospinal cord injury. (4) The principle of re-radiation therapy after radiation therapy, those with the following conditions should not be re-radiated. (1) the same target area (including nasopharyngeal and cervical targets) after radiotherapy for less than one year; (2) the emergence of radiation encephalopathy or radiation myelopathy after radiotherapy; (3) the total course of treatment for nasopharyngeal targets should not exceed three courses, and for cervical targets should not exceed two courses.
2. Radiation selection and irradiation range (1) Design of irradiation field: The principle of designing irradiation field is “small but not leaky”. The tumor involved parts should be included in the irradiation field, but the normal tissues in the irradiation field, especially those sensitive to radiotherapy, should be protected. If the nasopharynx and paranasal space are involved, the anterior nasal field can be irradiated. If the orbit is involved, the superior or inferior orbital field can be irradiated, and attention should be paid to protect the eye with lead sheet to prevent the occurrence of radioactive cataract. The scope of irradiation of the neck depends on the lesion of the lymph nodes. The radiation dose and time (1) continuous radiation therapy: 5 times a week, 200 cGY each time, total TD6000~7000 cGY/6~7 weeks.
(2) segmental radiation therapy: generally divide the radiation therapy into two segments, 5 times a week, 200 cGY each time, each segment about 3.5 weeks. Four weeks rest between the two segments, the total dose TD6500～7000cGY.
3, post-mounted intracavitary radiation therapy (1) Indications.
(1) Small limited lesions of nasopharynx (tumor thickness less than 0.5cm), located in the parietal, anterior or lateral wall; (2) Residual lesions after external irradiation or surgical resection of nasopharyngeal carcinoma conforming to ①.
(2) Treatment method: external irradiation plus intracavitary irradiation is often combined, with external irradiation amounting to 4500-6000 cGY, followed by intracavitary radiation 1~2 times after 1~2 weeks of external irradiation, with an interval of 7~10 days each time, and each dose is given at a dose point of 0.25cm under the mucosa, and 1000~2000 cGY/time.
4, radiation reactions and regression and its treatment (1) radiotherapy complications ① systemic reactions: including weakness, dizziness, loss of appetite, nausea, vomiting, tastelessness or change of taste in the mouth, insomnia or drowsiness, etc.. Individual patients may experience blood picture changes, especially leukopenia. Although the degree varies, it can usually be overcome with symptomatic treatment and completion of radiation therapy. If necessary, vitamins B1, B6 and C, and gastrofacial can be taken. If the white blood cell count drops below 3×109 children, radiotherapy should be suspended.
②Local reactions: including skin, mucous membrane, salivary gland reactions. The skin reaction is dry dermatitis or even wet dermatitis, which can be treated with local anti-inflammatory ointment based on 0.1% ice chips and talcum powder or lanolin. Mucosal reactions are characterized by congestion, edema, exudation and accumulation of secretions in the nasopharynx and oropharynx mucosa. In a few patients, swelling of the parotid gland can occur after 2Gy of parotid irradiation, and the swelling gradually decreases in 2-3 days. When irradiated with 40Gy, salivary secretion decreases significantly, while oral mucosal secretion increases, and the mucosa becomes congested and red and swollen. The patient’s mouth is dry and it is difficult to eat dry food. Therefore, excessive irradiation of the parotid gland should be avoided.
(2) Post-radiotherapy regression: mainly temporomandibular joint dysfunction and soft tissue atrophy fibrosis, radioactive dental caries and radioactive jaw spur osteomyelitis and radioactive encephalomyelopathy. There is no proper solution for reversal, symptomatic treatment and support methods are helpful. Over-irradiation of important tissues and organs should be strictly avoided.
(II) Surgical treatment
1. Excision of primary foci of nasopharyngeal carcinoma.
(1) Indications.
①Highly differentiated nasopharyngeal carcinoma, such as adenocarcinoma, squamous carcinoma grade I and II, early cases of malignant mixed tumor.
(2) Local recurrence of nasopharyngeal cancer after radiation therapy, with lesions limited to the posterior or anterior parietal wall, or involving only the edge of the pharyngeal fossa without infiltration of other parts, no difficulty in opening the mouth, and still in good health.
(3) If the radical dose of radiotherapy has been given, and the primary nasopharyngeal lesion has not disappeared, or if there is anti-radiation phenomenon, surgical excision is feasible after one month of rest.
(2) Contraindications.
①those with skull base bone destruction or paranasal infiltration, cranial nerve damage or distant metastasis.
(2) Contraindications: ①Patients with poor liver and kidney function and poor general condition.
(3) Surgery method: first tracheotomy intubation, surgery under general anesthesia. A horseshoe-shaped incision is made along the root of the palate at 0.5 cm from the alveolus, the mucosa of the hard crotch bone is incised, and the soft palate is peeled under the mucosa to remove part of the hard crotch bone plate and plastron. The mucosa of the nasal floor was transected at the junction of the hard and soft palate to expose the parietal wall of the nasopharyngeal cavity, the anterior part of both walls and the tumor. The nasopharyngeal mucosa was incised at the posterior edge of the nasal septum and the upper edge of the posterior nostril to reach the bone surface, and blunt or sharp separation was done.
2.Cervical lymph node dissection
(1) Indications: If the primary nasopharyngeal cancer lesion has been controlled after radiotherapy or chemotherapy, and the general condition is good, only residual foci or recurrent foci in the neck remain, with limited scope and activity, cervical lymph node dissection can be considered.
(2) Contraindications.
(1) residual foci or recurrent foci in the neck with deep neck tissue adhesions and fixation; (2) those with distant metastases or extensive skin infiltration; (3) those who are old and frail, with cardiopulmonary, hepatic and renal insufficiency and fail to correct.
3.Simple excision of cervical lymph nodes is feasible for single lymph nodes in the neck that are not sensitive to radiotherapy or for those who have isolated lymph node recurrence in the neck after radiotherapy. After local infiltration anesthesia, the skin and subcutaneous tissues on the surface of the metastases are incised and the metastases are completely removed together with some surrounding normal tissues. The wound can be dressed with slight pressure after surgery.
(C) Chemotherapy
1.Indications of chemotherapy for nasopharyngeal carcinoma (1) stage IV patients and stage IV patients with obvious lymphatic metastases; (2) any patient suspected to have distant metastases; (3) huge mass metastases of regional lymph nodes in the neck as induction chemotherapy before radiotherapy; (4) chemotherapy as sensitization before radiotherapy; (5) adjuvant chemotherapy after radiotherapy or surgical treatment.
2, commonly used combination chemotherapy program (Concomitant Chemo-radiotherapy) (1) CBF program: cyclophosphamide 600 ~ 1000mg / time, intravenous injection, the 1st and 4th day application. 5-Fluorouracil 500mg, intravenous injection, applied on the 2nd and 5th day, rest and l week after the course of treatment, total 4 courses of treatment. The effective rate was 60.8%.
(2) PFA regimen: cis-chloroplatinum 20mg and 5-fluorouracil 500mg, intravenous drip for 5 days; adriamycin 40mg, intravenous injection on the first day of the course. 3-4 weeks later, repeat once, there is a significant effect of shrinking tumor.
(3) PF regimen: cis-chloroplatinum 20mg/m2 and 5-fluorouracil 500mg/m2, intravenously for 5 days and then rest for 2 weeks, available for 2 to 3 courses. This regimen can be used to shrink the tumor before radiotherapy, or for cases of chemotherapy alone, with an efficiency of 93.7%.
3.Regional intra-arterial cannula perfusion chemotherapy can be used for nasopharyngeal carcinoma with upstaging and local recurrence after radiotherapy. Retrograde cannulation of superficial temporal artery or facial artery can be chosen. Combination or sequential treatment of several chemotherapeutic drugs with high potency and short duration of action is often chosen. Before administration, 2% procaine 2m1 is injected to prevent arterial spasm, and then anti-cancer drugs are injected, followed by 2.5% sodium citrate solution to fill the lumen and close the end of the tube. If continuous dosing is needed, 5% glucose saline with heparin solution 100m1 and anti-cancer drug 1500mg can be administered continuously for 24 hours.
Etiology
Epidemiological investigation suggests that the etiology of nasopharyngeal carcinoma may be related to the following factors: ① EBV infection. ②Environment and diet: environmental factors are also a cause of nasopharyngeal carcinoma. In Guangdong, it was found that the content of nickel, a trace element, in rice and water in areas with high incidence of nasopharyngeal cancer was higher than that in areas with low incidence. Nickel content in the hair of nasopharyngeal cancer patients is also high. Animal experiments have shown that nickel can promote nitrosamines to induce nasopharyngeal cancer. It has also been reported that consumption of salted fish and pickled food is a high risk factor for nasopharyngeal carcinoma in southern China, and it is related to the age of eating salted fish, the duration of consumption, the amount and the cooking method. Genetic factors: There are racial and family clusters of nasopharyngeal cancer patients, for example, the offspring of southern Chinese living in other countries still maintain a high incidence of nasopharyngeal cancer, which suggests that nasopharyngeal cancer may be a genetic disease.
Pathological changes]
(I) Preferred site and general morphology Nasopharyngeal carcinoma usually occurs in the top of the posterior wall of the nasopharynx, followed by the lateral wall, but rarely occurs in the anterior wall and the bottom wall. The general morphology of nasopharyngeal cancer is divided into five types, namely nodular, cauliflower, submucosal, infiltrative and ulcerative types.
(B) Growth and spread pattern The spread of nasopharyngeal carcinoma has its own regularity. The early nasopharyngeal cancer is confined to the nasopharynx and can be called confined type. As the tumor grows, it can spread to the adjacent sinus cavity, interstitial space and skull base directly. Nodular or cauliflower type tumors may protrude into the nasopharyngeal cavity, while infiltrative, submucosal and ulcerative types tend to grow in the submucosa. The cancer may grow into the nasal cavity, oropharynx, and may extend into the parapharyngeal space, pterygopalatine fossa or invade into the orbit. The cancer may expand directly upward and destroy the skull base bone and cranial nerves. The neck metastasis of nasopharyngeal cancer is through lymphatic drainage system, while distant metastasis may enter the blood circulation again through lymphatic system or cancer cells directly invade the surrounding blood vessels and enter the blood circulation and metastasize to distant organs.
(C) Histological classification
1. Carcinoma in situ: The concept of carcinoma in situ means that cancer cells have not yet broken through the basement membrane, and nasopharyngeal carcinoma in situ is no exception, and there must be intact basement membrane under the cancer focus. When carcinoma in situ cells proliferate in the form of buds or pegs to the subcutis, there is still a clear basement membrane separating the carcinoma cells from the underlying mucosal lamina propria. The diagnosis of nasopharyngeal carcinoma in situ is mainly based on cytological criteria, followed by consideration of histological arrangement and structure. Therefore, the cytologic criteria for the diagnosis of nasopharyngeal carcinoma in situ must be strictly controlled, i.e., the interstitial image must reach a well-recognized level. Compared with normal epithelial cells, in situ carcinoma cells have an increased nucleoplasmic ratio, i.e., their nuclear area is significantly larger.
2.Infiltrating carcinoma (1) Microinfiltrating carcinoma: It refers to a field of view in which the basement membrane is broken by cancer cells, but the infiltrating range does not exceed 400 times under the light microscope. The cell morphology is more obvious than that of in situ carcinoma with heterogeneous degree and infiltrative growth through the basement membrane.
(2) Squamous cell carcinoma: Although most nasopharyngeal carcinomas originate from columnar epithelium, most nasopharyngeal carcinomas are squamous cell carcinomas. To diagnose squamous cell carcinoma, the features of squamous differentiation must be present in the section. Squamous differentiation refers to: (1) keratinized beads; (2) intracellular and extracellular keratinization; (3) intercellular bridges; and (4) the arrangement of cells in the nests of cancer cells at a level similar to squamous epithelium, and the cells are not syncytial. According to the degree of squamous differentiation of cancer cells, nasopharyngeal squamous cell carcinoma can be classified into three levels: highly, moderately and poorly differentiated.
① Highly differentiated squamous cell carcinoma: Most of the cancer tissues with intercellular bridges or keratinization are called well-differentiated squamous cell carcinoma, or keratinized squamous cell carcinoma. Generally, there is no lymphocyte infiltration in the nest, but sometimes individual scattered lymphocytes can be seen. The boundaries of the nest are usually clear, and sometimes there is a complete membrane envelope. Most of these carcinomas are of fibrous tissue type. It is accompanied by infiltration of neutrophils, lymphocytes and plasma cells, but plasma cells are usually not too many.
Moderately differentiated squamous cell carcinoma: It refers to nasopharyngeal carcinoma with clear intercellular bridges and/or keratinization seen in the cancerous tissue, not individually but in a certain number. The number of either intracellular or extracellular keratinization is much less than that of highly differentiated squamous cell carcinoma. There were variable numbers of lymphocytic infiltrates in the nests, variable numbers of plasma cells around the nests, and interstitial changes similar to those of poorly differentiated squamous cell carcinoma, but different from those of highly differentiated squamous cell carcinoma.
(iii) Lowly differentiated squamous cell carcinoma: A certain number of cancer cells with intercellular bridges or intracellular keratinization were also seen under light microscopy, but the number was small. The nuclei of the cancer cells were deeply stained. The nucleoli are hypertrophied and often have some alkalophilic eosinophilic staining. The demarcation between cancer nests and interstitium is relatively clear, but they can also be intermingled with interstitium. The interstitium can be of various types, i.e. lymphocyte-rich infiltrative type, granulation tissue type, fibrotic type and intrinsic tissue type. Regardless of the type of interstitium, it is accompanied by a variable number of plasma cell infiltrates.
(3) Adenocarcinoma: Nasopharyngeal adenocarcinoma is extremely rare compared to nasopharyngeal squamous cell carcinoma, especially in areas with high incidence of nasopharyngeal cancer. According to the histogenetic view, adenocarcinoma must originate from the gland.
(1) Highly differentiated adenocarcinoma: The parenchyma and interstitium are clearly demarcated and the nests are more obvious. Some adenocarcinoma cells are arranged in glandular vesicles; some are arranged in high columnar duct-like structures; some are adenoid cystic carcinoma or sieve-like carcinoma; some are simple adenocarcinoma.
(2) Moderately differentiated adenocarcinoma: These are adenocarcinomas with a certain number of clearly formed glandular cavities seen in the cancerous tissue, but accompanied by some undifferentiated carcinoma structures. They are often the result of further interstitial transformation of the above highly differentiated