【Key Words】 trachea; schwannoma; surgical treatment

Trachea rare benign tumor, tracheal schwannoma quite rare to foreign reports of only 23 cases in 2005 [1], in 2007, only 22 cases reported in China [2  8] The lack of characteristic clinical and imaging findings, preoperative misdiagnosed or missed. Now reported two cases admitted to our department in recent years, and review of the literature, in order to improve the understanding of the disease.

    1 Clinical data

    Example 1: Male, 40 years old, was admitted to hospital on January 18, 2007 due to increased shortness of breath for six months after the activities for five days. Physical examination: patients speak inspiratory dyspnea performance, lung breath sounds clear. Fiber bronchoscopy: trachea from the glottis about 3cm see new oval biological surface blood vessels, clogging the lumen of more than 90%; cause bleeding asphyxia due to biopsy may be, it is not biopsy. Irregular soft tissue, chest CT scans see paragraph above endotracheal occupy almost entire trachea chamber, about 3cm in diameter, Figure 1a. The abdomen color ultrasound revealed no abnormalities. Preoperative diagnosis: tracheal tumor. January 22, 2007, under general anesthesia tracheal tumor resection. High degree of stenosis, tumor induced tracheal cavity estimated the intubation difficult to maintain systemic oxygen, so the first femoral artery – femoral vein CPB surgery to ensure oxygen supply. Take the neck curved incision plus previous paragraph sternum midline incision, L-type longitudinal sternotomy, exploratory surgery to see: tumor about 3.3cm × 3cm × 2.5cm, wide base even in the trachea and left posterior wall membranous, occupy the trachea chamber 90% , no tumor involvement of the surrounding structures. From the operative field by tracheal incision into the endotracheal tube to the lower segment endotracheal mechanical ventilation, stop femoral artery – femoral vein bypass (bypass time 36min). Resection of the tumor where tracheal segment ring about 3.5cm the tracheal stump tissue health, tracheal stump anastomosis pretracheal pedicled flap embedded tracheal anastomosis. Cured. Pathological diagnosis: tracheal schwannoma. Grossly: irregular, grape-like, rich in blood vessels with unclear tracheal wall sector, as shown in Figure 2a; microscopy density and white: the tumor cells, tumor cells were spindle-intensive areas cytoplasmic staining, cell sector is unclear The nuclei were fusiform, wavy or comma-shaped tumor cells were wispy and palisading, as shown in Figure 2b; immunohistochemical staining: S-100 +, Vimentin in + Desmin  Figure. 3a ~~ 3c. Follow-up in December, asymptomatic, capable of performing manual labor; the reexamination fiber bronchoscopy and chest CT see tracheal smooth, no new biological, as shown in Figure 1b.

    Example 2: female, 38 years old, admitted to hospital because of paroxysmal cough and March. Previously outside the hospital for the treatment of bronchial asthma, the symptoms were not relieved. Physical examination: lungs could be heard and wheezing sound. Fiber bronchoscopy: the subcarinal on the 2cm tracheal lumen see a tumor blocking the lumen of about 50%, pedicle and the trachea the left wall is connected, you can move up and down with respiration. Chest CT and three-dimensional reconstruction of the left posterior wall of the lower trachea tissue mass, approximately 1.2cm x 1.0cm, uneven density. Clinical diagnosis: lower segment tracheal primary tumor. July 15, 2006 tracheal tumor resection. Take the right chest posterolateral incision through the 5th intercostal chest, intraoperative exploration oval masses see the left wall of the trachea, solid, capsule, about 2.2cm × 1.8cm × 1.5cm, gray-yellow, smooth surface . The surgical removal of three cartilage rings and tumors, the two ends of the line of end-to-end anastomosis, anastomotic azygos chip embedded. Intraoperative ventilation oral endotracheal tube is inserted to the tumor above the line of positive pressure oxygen ventilation, tracheostomy from the operative field by tracheal incision to insert another the tracheal catheter through the left main bronchus mechanical ventilation after the removal of the tumor resection far end of endotracheal intubation, the proximal end of the endotracheal tube over the surgical incision site inserted into the left main bronchus mechanical ventilation. Pathological diagnosis: tracheal schwannoma. Microscopically, the tumor cells fusiform fibrous capsule tumor. The patients were followed up for 18 months, asymptomatic, can be engaged in manual work.

    2 Discussion

    Schwannoma, a tumor originated in the nerve sheath (Schwann) cells, Schwann, low incidence of 30 to 40 years old for the high incidence of age, can occur in various parts of the human body, but more common in the flexor side of the head and neck and limbs [9]. Mostly substantive enveloped tumors grow slowly; rarely malignant cases. Special performance of imaging studies: smooth surface, clear boundary, surrounding tissue invasion signs, such as a series of benign performance, larger intratumoral hemorrhage or necrosis cystic uneven density [10]; Pathology examination can be confirmed based on its unique morphology, immunohistochemistry S  100 and Vimentin positive and confirmed that the tumor originated in Schwann cells [11]. The two cases in addition to parts in line with the above characteristics.

    Trachea fewer primary tumors were malignant tissue types are more common in squamous cell carcinoma and adenoid cystic carcinoma; quite rare benign tumor [12], while the primary endotracheal schwannomas are even rarer. So far, the the domestic only reported 22 cases. Were located in the lower segment of the trachea, and more often in adults, located in the subcarinal near [2]. Existing reports, the youngest 5 years old, maximum 78 years, women slightly higher incidence [1]. Occult onset, early diagnosis is difficult. The main symptoms of the majority of patients with irritating cough or difficult to control wheezing like episodes [13]. 2 patients characteristics: Example 1 larger tumors, is greater than the reported maximum tumor 3cm × 2cm × 2cm [2], and are at most trachea schwannoma trachea segment, reported in the literature as in Example 2, is located in lower segment carina near The disease can occur in the trachea of ​​each paragraph, can occur even in the bronchus and lung [14  15]. The disease is easily missed or the same as in Example 2 misdiagnosed as bronchial asthma, reason: 1, rare admissions of physician awareness and vigilance is not enough; occult onset, early no obvious symptoms, when the tumor increases the tracheal cavity obstruction or secondary pulmonary infection caused to a certain extent, appear similar to bronchial asthma or lung infections like performance. Therefore, to improve the modern understanding of the disease and the application of CT, fiber bronchoscopy examination methods to improve the diagnosis of this disease.

    Surgical resection is the most effective way to treat the disease [1  5], while maintaining the the effective oxygen for surgery to protect patient safety and the prerequisite for the success of surgery. Typical of the two cases of anesthesia and oxygen supply. Example 2 tracheal lumen obstruction is not heavy, and the tumor from the glottis sufficient length for endotracheal intubation, so the use of large-caliber endotracheal tube is inserted to the lesion above the tracheotomy and then with a small-caliber catheter through the left main bronchus, ventilation to solve surgery. The method is simple and feasible, the patient physiological interference, but not for the high degree of obstruction in patients with tracheal like Example 1, because intubation may cause choking or can not guarantee the passive situation of oxygen; therefore, need to pre-establish cardiopulmonary bypass guarantee for the oxygen case surgery, to be free trachea and cut the bottom of the tumor from the surgical field into the endotracheal tube, thus stop the pump. Surgery to tracheal rings the annular sleeve resection of the tumor where the tracheal stump as the preferred surgical anastomosis trachea, its key is the complete removal of the tumor and the surrounding normal tissue [1].

    This disease is a rare tracheal tumor diseases easily misdiagnosed, CT and fiber bronchoscope applications found in the early stage of the disease and an important role in the diagnosis. Complete surgical resection of the tumor is the effective treatment of this disease, common surgical procedures the annular sleeve resection of the tumor where tracheal rings, and then ends anastomosis tracheal continuity, maintain an effective intraoperative oxygen supply is essential, generally feasible after the second surgery tracheotomy intubation, if necessary, to establish cardiopulmonary bypass guarantee the oxygen supply. Very low recurrence rate after complete resection of the tumor, the prognosis is good, satisfied with the postoperative quality of life and survival time, has so far reported no recurrence or malignant.