Primary tracheal neoplasms are rare and uncommon, accounting for less than 0.01% of all tumors and for about 0.2% of respiratory malignant lesions.
The most common histologic types are squamous cell carcinoma representing about 50-66% and adenoid cystic carcinoma accounting for 10-15%.
Occasionally extrathyroid extension of thyroid malignancies involve the trachea. Widely aerodigestive tract invasion occurs in 1-8% of patients with thyroid cancers. De facto the trachea is the most common site of invasion with an incidence of 35-60%.
Surgery is the treatment of choice for both benign and malignant tracheal neoplasms. Radiotherapy is indicated as an adjuvant to resection or for unresectable tumors or for palliation of severe symptoms.
The maximal length of trachea that can be resected has always been a crucial issue. Grillo performed cadaveric studies and found that with a standard tension of 1000-1200 g, it was possible to resect up to a median length of 4.5cm without producing much anastomotic tension. However increasing technical expertise has proved it is possible to resect with end to end anastomosis up to 50% of the length of trachea in adults. Younger age, elasticity of tracheal wall and the absence of previous treatment have positive influence on the extent of resection.
Here we present three cases, one primary tracheal adenoid cystic carcinoma and two with extrathyroidal extension of papillary carcinoma, that underwent tracheal resection and primary anastomosis.
CASE 1
A 46 year old female presented with complaints of breathing difficulty for five months. She had been on medical management with bronchodilators and inhalational steroids, but they provided only momentary relief. She was then evaluated with CT scan of neck and thorax by a pulmonologist which revealed a subglottic growth. Rigid bronchoscopy was performed which revealed a polypoidal lesion 1.5 cm below the vocal cords arising from the right lateral wall, reducing the lumen to 20%. The mass extended from second tracheal ring to about three centimetres distally. It was debulked and sent for histopathologic examination which showed features of adenoid cystic carcinoma. Rest of her clinical and laboratory examination did not reveal any significant abnormalities. She then underwent primary tracheal resection for a length of 4.6cm with a margin of around lcm both proximally and distally. The cut ends were anastomosed primarily. Stay sutures were placed from skin over the lower jaw to the clavicle (Guardian sutures) to maintain neck flexion for a period of two weeks. The patient then underwent adjuvant radiotherapy six weeks post surgery and is now alive and well after a period of two years with no fresh respiratory symptoms.
CASE 2
A 51 year old female patient presented with a history of swelling in the neck for six months, gradually increasing in size. She also developed difficulty breathing, more in supine position two months later. An FNAC was done which revealed papillary carcinoma of thyroid. CT imaging of the neck showed an exophytic mass lesion in the right lobe of thyroid infiltrating the right lateral wall of trachea and enlarged right level Ill lymph node. Upper GI scopy and flexible bronchoscopy was done which revealed growth in the right wall of trachea around 1 cm below the subglottis with partial lumen obstruction.
After routine pre operative evaluation she underwent covering tracheostomy and total thyroidectomy with trachea neck dissection along with resection of anterior and right lateral wall of trachea from the first ring to fifth ring. The posterior and left lateral wall was then divided in a diagonal fashion and rotated and brought anteriorly Fig oftracheal 4: Brochoscopic infiltrationimage and primary anastomosis was done. Wound was closed with drain in situ and neck kept in flexion with guardian sutures from chin to clavicle. In post operative period she was managed with parenteral antibiotics, tracheostomy and drain care. Drain was removed after one week. Guardian sutures and tracheostomy tube were removed in the second post operative week. Patient is now one month post op and is comfortable without any respiratory symptoms.
CASE 3
A 64 year old female patient had a history of right sided neck swelling two years ago for which she underwent right hemithyroidectomy. The histopathology revealed papillary carcinoma of thyroid. She was advised completion thyroidectomy but patient defaulted. She now presented with swelling on both sides of the neck for five months and hoarseness for the last three months. A CT neck was done which revealed a heterogenous soft tissue lesion in the region of the left lobe of thyroid and bilateral cervical lymphadenopathy. FNAC of the neck node was done which showed evidence of papillary carcinoma thyroid. Upper GI scopy and bronchoscopy revealed left vocal cord palsy and no other abnormality. Routine pre operative evaluation was done and patient was taken up for surgery. She underwent completion thyroidectomy with bilateral type Ill modified radical neck dissection. The left recurrent laryngeal nerve was seen to be entering the tumor, hence was sacrificed. On mobilizing the thyroid from its bed it was seen to be adherent to the first and second tracheal cartilage. Hence the anterior wall of the same was excised. Cut ends of the trachea were sutured primarily and reinforced with sternomastoid muscle cover. Tracheostomy was done and skin closed with drain in situ. Stay sutures were not put in view of shorter, partial resection with no tension in the anastomosis, but patient was nursed in flexed neck position. Drain was removed one week post operatively and tracheostomy decanulated after two weeks. Patient is now three weeks post operation and is symptom free.
Conclusion
In most tracheal malignancies the symptom presentation is often misleading and a correct diagnosis may be delayed by months to years. Clinical suspicion plays a fundamental role and endoscopic and CT evaluation remain the cornerstones in the diagnostic pathway. Appropriate surgical resection and reconstruction is still the best modality to achieve a long term survival with a decent quality of life. However, this remains a challenging procedure and a vast experience and an in depth knowledge of every detail, from patient selection to surgical approach and reconstruction techniques are absolutely essential.
