Primary tracheobronchial tumor

　　1. Etiology

　　Tracheal tumors can be divided into three types according to the degree of differentiation: malignant, low-grade malignant, and benign. Malignant tumors include squamous cell carcinoma, adenocarcinoma, and poorly differentiated carcinoma, among which squamous cell carcinoma is the most common, accounting for about 50% of primary tracheal tumors; low-grade malignant tumors include adenoid cystic carcinoma, mucoepidermoid carcinoma, and carcinoid, among which adenoid cystic carcinoma is the most common, accounting for about 30% of primary tracheal tumors; benign tracheal tumors include leiomyoma, hamartoma, papilloma, neurofibroma, salivary gland mixed tumor, hemangioma, etc.; there are also some rare tumors, such as carcinosarcoma, chondrosarcoma, and chondroma, etc.

　　Primary tracheobronchial tumors originate from squamous epithelial cells of the mucosal epithelium, adenocarcinoma, and papilloma; from mucosal glands or submucosal glands, there are adenoid cystic carcinoma and mucoepidermoid carcinoma; from argentaffin Kulchitsky cells in the mucosal epithelium, there are poorly differentiated carcinoma and carcinoid; from mesenchymal tissue, there are leiomyoma, hemangioma, chondroma, neurofibroma, hamartoma, and carcinosarcoma, etc. Primary tracheobronchial tumors, whether benign or malignant, often originate from the two posterior angles at the junction of the membranous part and cartilage ring on the posterior wall of the tracheobronchus.

　　2. Pathogenesis

　　Although primary tracheal and bronchial tumors belong to upper respiratory tract tumors, due to the relationship of lesion location, their clinical symptoms can be completely different. While benign tumors and malignant tumors of the trachea or bronchus are compared, their clinical symptoms have commonalities. In the early stage of the lesion, a small amount of blood may be present in the sputum, which is not easy to attract the attention of patients, and it is also not easy to find such intraluminal lesions in general clinical examination. Diagnosis is often delayed.

　　Complications of primary tracheobronchial tumors:

　　1. Airway obstruction: Due to atypical early symptoms and mainly manifested as cough, sputum, asthma, or a little blood in the sputum, it cannot be diagnosed correctly in time. As the tumor grows and occupies the airway, affecting respiration, if not treated in time, the condition can develop to a very dangerous state, easily leading to patient death.

　　2. If it is in the late stage of malignant tumor, the patient may present with symptoms such as hoarseness, difficulty swallowing, compression of mediastinal organs and tissues, and complications such as tracheoesophageal fistula, cervical lymph node metastasis, and pulmonary purulent infection.

　　Whether benign or malignant, the main cause of symptoms in tracheal tumors is the obstruction of the lumen and respiratory difficulties. Only when the tracheal lumen is blocked by 1/2 to 2/3 does severe respiratory difficulty occur. Common symptoms in tracheal tumor patients include dry cough, shortness of breath, asthma, wheezing, dyspnea, cyanosis, etc. Physical activity, changes in body position, and tracheal secretions can all worsen symptoms. Malignant lesions may cause hoarseness, difficulty swallowing, etc. Recurrent episodes of unilateral or bilateral pneumonia may occur. If the lesion is located at the junction of one tracheal bronchus, even if the tracheal stenosis is very obvious, only one side of pneumonia can be seen. If the tumor is located in the trachea, bilateral pneumonia can be seen. In addition to symptoms of tracheal obstruction, persistent and stubborn cough is also a clinical manifestation of primary tracheal tumors. Whether benign or malignant, when the lumen is not completely blocked, it often manifests as purulent infection of the lung, bronchiectasis, lung abscess, etc.; when the lumen is completely obstructed, it manifests as atelectasis.

　　1. Characteristics of various benign tracheal tumors

　　1. Papilloma:

　　Papillomas are common in the larynx, while papillomas originating from the bronchial tree are rare. This disease is more common in children, less common in adults. In children, it is often multiple, while in adults, it is solitary and can undergo malignant transformation. The etiology may be related to inflammatory reactions caused by viral infections. Papillomas originate from the tracheal and bronchial mucosa, presenting as irregular papillary villous protrusions, with vascular connective tissue as the core, covered by several layers of differentiated mature epithelial cells arranged radially. The superficial layer is squamous epithelial cells, which are keratinized.

　　The tracheal wall phase, CT is helpful for diagnosis, and fiberoptic bronchoscopy is a reliable method for definite diagnosis. Under bronchoscopy, papillomas appear like cauliflower, pale red, fragile and prone to bleeding. The base is wide or has a thin pedicle. Preparations should be made for biopsy to avoid bleeding or tumor detachment causing asphyxiation.

　　Tracheal papillomas grow in clusters, attached to the tracheobronchial mucosa through a finer pedicle. Papillomas are brittle and easily fall off. Papillomas have the characteristics of multifocality and postoperative recurrence. According to the clinical experience of large groups of tracheal tumor surgical treatments, no treatment method can prevent the recurrence tendency, which brings certain difficulties to clinical treatment.

　　Small benign papillomas can be removed through fibrobronchoscopy, or treated with laser therapy through fibrobronchoscopy, or removed by tracheotomy. For those with a larger size, broader base, and suspected malignancy, sleeve resection of the trachea or limited resection of the lateral wall of the trachea should be performed.

　　2. Fibroma:

　　Tracheal fibromas are rare, with the tumor surface covered by normal tracheal mucosa. Under bronchoscopy, the tumor appears as a circular, grayish-white mass with a smooth surface, a broad base, non-mobile, and not easy to bleed. It often appears with multiple biopsies all being negative.

　　3. Hemangioma:

　　They can be cavernous hemangiomas, vascular endothelioma, vascular pericytoma, etc., and can originate from the trachea or extend into the trachea from the mediastinal hemangioma. Hemangiomas can diffusely infiltrate the tracheal mucosa and narrow the tracheal lumen, or they can protrude into the tracheal lumen to cause obstruction. Under fibrobronchialscopy, the hemangiomas protruding into the lumen are soft, red, and polypoid. Biopsy is generally prohibited to avoid bleeding and asphyxia. Treatment can be endoscopic resection, laser therapy, or surgical operation.

　　4. Neurofibroma:

　　Tracheal nerve sheath tumors are benign tumors of the nerve sheath, often solitary, encapsulated, hard in texture, and the tumor can be pedunculated and protrude into the tracheal lumen. Under fibrobronchoscopy, circular, hard, and smooth masses can be seen on the tracheal wall. Histologically, there is an alternation of spindle cells and mucinous matrix, and the nerve sheath cells are arranged in a typical lattice pattern. Tracheal nerve sheath tumors can be removed endoscopically or by tracheotomy.

　　5. Fibrous histiocytoma:

　　Tracheal fibrous histiocytoma is rare, commonly located in the upper third of the trachea, presenting as a polypoid mass, soft in texture, and grayish-white. It protrudes into the lumen. It is difficult to differentiate between benign and malignant histologically, mainly based on whether the tumor has invaded externally, metastasized, and has a large number of nuclear mitotic figures. Fibrous histiocytoma often recurs locally after resection, so the surgical range can be wider, and local extended resection or sleeve resection of the trachea should be performed. Postoperative treatment of malignant fibrous histiocytoma of the trachea should be supplemented with radiotherapy and chemotherapy.

　　6. Lipoma:

　　Tracheal lipomas are extremely rare, originating from differentiated mature fat cells or primitive mesenchymal cells. Subtle red or yellow circular masses can be seen under the fibrobronchial tube, blocking the lumen, with a smooth surface, mostly broad-based, sometimes with a short pedicle, covered by bronchial mucosa, and soft in texture. Tracheal lipomas can be removed through bronchoscopy and the base burned with a laser. When the tumor is large and has penetrated the cartilage ring into the trachea, local resection of the tracheal wall or sleeve resection of the trachea should be performed.

　　7. Cartilaginous tumor:

　　Tracheal cartilaginous tumors are extremely rare, with only a few case reports in the literature. The tumors are round, hard, and white, with part located within the tracheal wall and part protruding into the tracheal lumen. Small cartilaginous tumors can generally be removed through bronchoscopy, and recurrence and malignant transformation can occur after tracheal cartilaginous tumor surgery.

　　8. Leiomyoma:

　　Tracheal leiomyoma often occurs in the lower third of the trachea, originating from the submucosal layer of the trachea. It is round or oval, with a smooth surface, protruding into the lumen. The mucosa is pale. Histologically, the tumor is composed of well-differentiated, arranged in a crisscross pattern of fusiform cell bundles. Tracheal leiomyoma grows slowly, and it can be removed through fiberoptic bronchoscopy when the tumor is small. When the tumor is larger, a sleeve resection of the trachea should be performed.

　　9. Hamartoma:

　　The tumor is round or oval, with a complete capsule, usually with a small pedicle connected to the wall of the tracheobronchus. The tumor surface is smooth and hard, and it is not easy to obtain tumor tissue with fiberoptic bronchoscope biopsy forceps. Treatment can be laser ablation, vaporization of the tumor, or removal with biopsy forceps.

　　Two, Characteristics of Malignant Tumors of the Trachea

　　1. Tracheal squamous cell carcinoma:

　　It commonly occurs in the lower third of the trachea, accounting for 40% to 50% of primary tracheal malignant tumors. It can manifest as a well-localized protruding lesion or an ulcerative type, showing infiltrative growth. It is prone to invade the recurrent laryngeal nerve and esophagus. Scattered multiple squamous cell carcinomas in the trachea can occasionally be seen, and ulcerative squamous cell carcinomas can also involve the entire length of the trachea. About one-third of primary tracheal squamous cell carcinoma patients have deep mediastinal lymph node and lung metastasis at the time of initial diagnosis. The spread of tracheal squamous cell carcinoma often occurs first in the adjacent paratracheal lymph nodes or directly invades the mediastinal structures.

　　2. Tracheal adenoid epithelial carcinoma:

　　They account for about 10% of tracheal malignant tumors, with small size, hard texture, and little necrosis. Patients often have deep invasion of the tumor at the time of consultation, with poor prognosis. Other rare tracheal carcinomas include oat cell carcinoma. Malignant tumors originating from the tracheal stroma include leiomyosarcoma, chondrosarcoma, liposarcoma, etc. Carcinoma and chondrosarcoma of the trachea may be cured by surgical resection.

　　Three, Characteristics of Low-Grade Malignant Tumors of the Trachea

　　1. Carcinoid:

　　Kulchitsky cells originating from the tracheobronchial mucosa contain neurosecretory granules. Pathologically, they are divided into typical carcinoids and atypical carcinoids. Carcinoids are commonly found in the main bronchus and its distal bronchi. Clinical symptoms are related to the location of the tumor. Carcinoids located in the main bronchus can cause recurrent lung infections, expectoration of blood-tinged sputum, or hemoptysis. A few carcinoids are accompanied by carcinoid syndrome and Cushing syndrome. Fiberoptic bronchoscopy can determine the location of the tumor and directly observe its shape. Pathological diagnosis can be obtained through biopsy, but the positive rate of biopsy is only about 50%, because Kulchitsky cells are distributed in the basal layer of the bronchial mucosal epithelium. The surface of the tumor growing inward often covers a complete mucosal epithelium, so it is not easy to obtain tumor tissue during biopsy. The principle of surgical treatment for tracheobronchial carcinoids is to remove the tumor as much as possible while retaining the normal tissue to the maximum extent. For tumors located in the main bronchus, middle segment, and lobar bronchi, if there are no obvious irreversible changes in the distal part of the patient, bronchoplasty should be attempted. If there is lymph node metastasis at the hilum of the lung, simultaneous pulmonary hilum lymph node dissection should be performed. If the distal lung tissue has obvious irreversible changes due to repeated infections, lobectomy or pneumonectomy should be performed. Carcinoids are somewhat sensitive to radiotherapy, and adjuvant radiotherapy can be used after surgery.

　　The prognosis of surgical treatment for tracheobronchial carcinoid is good, with a 5-year survival rate of up to 90%, while the prognosis of atypical carcinoid is relatively poor.

　　2. Adenoid cystic carcinoma:

　　Adenoid cystic carcinoma is more common in women, with about 2/3 occurring in the lower segment of the trachea, near the carina and the starting level of the right and left main bronchi. The tumor originates from the mucous secretion cells of the gland ducts or glands and can grow like a polyp. However, it often infiltrates circumferentially along the tissue between the tracheal cartilage rings, blocking the lumen. It can also directly invade the surrounding lymph nodes. Tumors that protrude into the lumen of the trachea usually do not have a complete mucosal covering, but they rarely form ulcers. The adenoid cystic carcinoma at the carina can grow into both main bronchi.

　　Adenoid cystic carcinoma is histologically divided into pseudo-acinar type and medullary type. The presence of PAS-positive mucus within and outside the cells is its main characteristic. Adenoid cystic carcinoma has the characteristic of slow growth in clinical practice, and the course of the disease can be very long. Even if distant metastasis occurs, its clinical behavior is relatively benign. Large tracheal adenoid cystic carcinomas often cause mediastinal displacement first. The adenoid cystic carcinoma of the trachea can infiltrate and grow along the submucosal layer of the trachea, involving a long segment of the trachea, and it is not distinguishable grossly. Some lesions have a higher degree of malignancy, and there are already metastases to the pleura and lung before the primary tumor in the trachea is discovered. Almost all patients with tracheal adenoid cystic carcinoma seen in clinical practice have undergone repeated local resection or segmental resection of the tracheal tumor, and these patients often have distant metastasis.

　　Treatment includes surgical resection, endoscopic resection or laser treatment, and chemotherapy can be used as adjuvant therapy. Adenoid cystic carcinoma is not very sensitive to radiotherapy, but it can be used for cases where the lesion cannot be completely resected, there is mediastinal lymph node metastasis, or there are surgical contraindications.

　　3. Mucinous epidermoid carcinoma:

　　The incidence is relatively low, and it mostly occurs in the main bronchus, the middle segment bronchus, and the lobar bronchus. The tumor surface is generally covered with mucosa, and its clinical manifestations are closely related to the location of the tumor. Pathological diagnosis can be confirmed by bronchoscope biopsy.

　　Mucinous epidermoid carcinoma has infiltrative characteristics in clinical practice, and it metastasizes along the lymphatic pathway. Surgical treatment includes pulmonary lobectomy or total pneumonectomy, lymph node dissection at the hilum and mediastinum, and adjuvant radiotherapy after surgery. Mucinous epidermoid carcinoma is prone to recurrence after surgery, and its prognosis is worse than that of adenoid cystic carcinoma and carcinoid.

　　1. Diet principles

　　It is advisable to choose foods that can enhance the immune function and help in inhibiting the action of cancer cells by drugs, such as sweet almonds, Job's tears, water chestnuts, oysters, jellyfish, bighead fish, sea turtles, clams, sea cucumbers, and sea buckthorn.

　　二、辩证实施

　　1、肿瘤浸润支气管壁有阵发性、刺激性呛咳，无痰或仅有少量白色泡沫样粘痰的患者，可用：白果、萝卜、荠菜、杏仁酥、枇杷、橄榄、或文旦皮泡茶喝。

　　2、痰液粘稠难咳出者，可食用海蜇、荸荠、蛤蜊葱花汤、米仁、海带、昆布、紫菜等。

　　3、并发感染时痰液可呈黄色和脓性：冬瓜、薏苡仁、丝瓜、荠菜、萝卜、荞麦。

　　4、久咳体虚者：茼蒿菜、荠菜、芝麻、山药、柿子、石榴、无花果、松子、核桃、鹌鹑蛋、鲤鱼、淡菜、罗汉果、琼脂、桃子、橙、柚子等。

　　5、发热者：黄瓜、冬瓜、莴苣、百合、苋菜、荠菜、石花菜、鱼腥草、马齿苋、糜子、西瓜、菠萝、梨、柿子、橘子、柠檬、橄榄、桑椹子、荸荠、茄子、发菜、鸭肉等。

　　6、咯血者：青梅、藕、甘蔗、梨、柿子、海蜇、海参、莲子、菱、海带、荞麦、黑豆、豆腐、百合、荠菜、茄子、牛奶、鲫鱼、龟、乌贼、黄鱼鳔、甲鱼、牡蛎、淡菜等。

　　7、胸痛患者：油菜、丝瓜、猕猴桃、核桃、荞麦、杨桃、杏仁、茄子、桃子、芥菜、鹌鹑、蟹、橙、鲫鱼等。

　　尿常规胸部平片核磁共振成像(MRI)纤维支气管镜检查血常规便常规肿瘤标志物检测造影检查肺功能检查经支气管镜肺活检

　　一、X线检查

　　气管的后前位及侧位体层像，气管分叉体层像对诊断气管，支气管肿瘤有重要意义，这些检查可清晰地显示气管腔内肿瘤的轮廓，位置，范围和病变与邻近器官的关系，良性肿瘤可有钙化，基底有细蒂，恶性肿瘤基底宽，边界，轮廓均不完整，行后前位气管体层像时，嘱病人说“E”，可以很好地显示后前方向的喉部以及气管全长的详情；照侧位气管像时做吞咽动作，能使喉部抬高，从而清晰地显示喉与气管的关系；左，右后斜位气管体层像对显示器官，尤其是支气管各主要分支的病变有很大帮助。

　　二、CT检查

　　对气管肿瘤的诊断有很大帮助，CT可显示气管腔内的密度增高的软组织影，多为偏心性，气管壁增厚，气管呈不规则狭窄，大约10％的气管肿瘤沿气管周围生长，30％～40％的气管肿瘤直接累及纵隔，支气管肿瘤在CT上可表现为向腔内生长或向腔外浸润，引起支气管不全或完全梗阻，出现阻塞性肺炎或肺不张，根据支气管肿瘤的浸润程度，Naidich等将其分为6种表现：

　　1、支气管壁显示正常；

　　2、支气管壁均匀狭窄；

　　3、支气管不规则狭窄；

　　4、支气管腔完全阻塞；

　　4. Complete obstruction of the bronchial lumen;

　　5. Tumor in the bronchial lumen;

　　6. Compression and displacement of the bronchus

　　Third, MRI examination

　　The image of the trachea can be reconstructed from the transverse, sagittal, and coronal sections, so it can provide very accurate location, range, and infiltration extent of the tracheal tumor. For bronchial tumors, MRI can show the situation and extent of obstruction inside the bronchial lumen more clearly than the bronchial bifurcation tomography X-ray by reconstructing the coronal view of the tracheal bifurcation.

　　Fourth, bronchography examination

　　When the obstruction of tracheobronchial tumors is not serious, bronchial iodine oil contrast imaging can also be performed, which can more clearly show the location and extent of the luminal obstruction.

　　Fifth, fiberoptic bronchoscopy examination

　　Dietary taboos for patients with primary tracheobronchial tumors

　　1. Do not eat spicy food, do not eat cold food, oh do not eat lychee and tangerine, it is very easy to cough, do not eat high sugar, do not add vinegar and alcohol to the dishes, oh it is best not to drink tea, bamboo shoots should not be eaten either, I once ate some and coughed to death, oh also eat less yellow croaker, hairtail fish, shrimp, crab, fatty meat, garlic, scallion, and chive should not be eaten.

　　1. Treatment

　　Once the tracheal tumor is diagnosed, surgical treatment should be considered first. The main purpose of tracheobronchial surgery is to completely remove the lesion, eliminate obstruction, relieve ventilation disorders, and reconstruct the respiratory tract. Surgical procedures should be selected according to the size and location of the tumor for the resection of the affected tracheal segment and tracheal reconstruction.

　　1. Indications for surgery

　　Once the tracheal tumor is diagnosed, surgical resection should be considered first. Although efforts are made to remove the lesion completely, the length of the trachea that can be resected is limited, and the pros and cons should be weighed. For patients with extensive lesions, the trachea may be resected too long, which can affect healing due to excessive tension at the anastomosis after surgery, so surgical treatment is only suitable for a limited number of cases. For patients with long lesions and obvious external invasion, radiotherapy should be performed first before considering surgery; when the tracheal tumor is accompanied by laryngeal nerve paralysis causing hoarseness or compression of the superior vena cava causing superior vena cava syndrome, surgery should be contraindicated; if there is distant metastasis, it is generally contraindicated for surgery, but if the patient has obvious tracheal obstruction that seriously threatens life, simple surgery can be performed to relieve tracheal obstruction, palliatively solve the ventilation disorder, and alleviate symptoms.

　　2. Preoperative precautions

　　(1) For small benign tumors in the trachea with pedicles, the tracheal wall can be incised, and the pedicle or the mucosa with the pedicle can be resected in the lumen. Only the local dissection of the anterior wall of the trachea should be performed, and efforts should be made to avoid dissection of both walls to damage the vascular chain of the lateral wall, which may affect healing.

　　(2) For benign tumors with a wide base and small, localized, low-grade malignant tumors, the entire tracheal wall involved can be resected, and the defect in the tracheal wall can be repaired with pericardium, pleura, and fascia, etc. If local wedge resection is performed, it can also be directly sutured.

　　(3) For tumors that grow in a ring shape or have a large range of involvement, sleeve resection and anastomosis should be performed. The extent of resection should

　　(4) The tumor near the cricoid cartilage cannot be excised in a circular manner, so the outer cavity is narrow and easy to damage the vocal cords; the posterior angle of the cricoid cartilage must be preserved, otherwise it can cause injury to the recurrent laryngeal nerve; when the cricoid cartilage is invaded, only laryngectomy and permanent tracheostomy in the neck can be performed.

　　(5) The tumor of the tracheal carina should be resected and reconstructed, and various methods of free trachea should be flexibly applied during the operation to reduce the tension at the anastomosis.

　　(6) When malignant tumors originating in the left, right bronchi and upper lung involve the carina, subtotal pneumonectomy and resection of the carina and the corresponding lung lobe and the entire lung should be performed.

　　II. Prognosis

　　The prognosis of tracheal and bronchial tumors is closely related to the histopathological morphology. Squamous cell carcinoma develops rapidly, infiltrates and grows around, affects breathing and eating, and has a poor prognosis; adenoid cystic carcinoma, carcinoid, etc., develop slowly, have low malignancy, infiltrate and can metastasize, but the survival time with the tumor is long, and the prognosis is still good; tracheal papilloma is benign but has the characteristics of multiple occurrences and recurrence, the clinical treatment is more complex, and special attention must be paid; neurofibroma is benign, with a good prognosis, but can also locally recur; the tumors of mesenchymal tissue such as chondroma, capillary hemangioma, and hamartoma have a good prognosis and can be cured by local resection.