Volume 4, Issue 1 , Pages 25-28, January 2009
Airway obstruction due to a retro-tracheal inflammatory myofibroblastic tumour in a 19-month-old boy
Article Outline
Summary
Inflammatory myofibroblastic tumours (IMTs) are benign slow growing lesions with a distinct histological appearance. The majority of these type of lesions have so far been reported in adolescent children presenting with airway compromise. We describe the first report of an IMT in a 19 month old child that presented with airway obstruction. This lesion was treated by complete excision via an anterior trans-tracheal approach.
Keywords: Tracheal inflammatory pseudotumour, Airway obstruction
1. Introduction
Inflammatory myofibroblastic tumours (IMTs) represent a subset of a heterogeneous group of lesions consisting of tumour-like masses of spindle and inflammatory cells. They normally follow a course of slow benign growth and have a distinct histological appearance. Since clinically and radiologically these lesions can be suspicious of a more malignant process, this type of lesion has also been described as an Inflammatory Pseudotumour [1]. IMTs most commonly involve the respiratory system [2]. However, overall they are uncommon findings within the respiratory tract and represents less than 1% of all tumours in the lungs and airways [3]. There have been only a few reports describing airway IMTs in adolescents [4], [5], with the youngest case reported so far has been an 8-year-old child [6]. We describe the first report of a retro-tracheal IMT in a 19-month-old child that presented with airway obstruction. This lesion was treated by complete excision via an anterior trans-tracheal approach.
2. Case report
A 19-month-old boy presented to his local hospital in Tehran with a 10-day history of noisy breathing. An initial diagnosis of asthma was made and he was commenced on medical treatment for this. At presentation his mother had also noted a change in her son's voice. A few days later he was admitted to the same hospital with severe difficulty in breathing. At this time an aspirated foreign body was suspected and an urgent microlaryngoscopy and bronchoscopy performed which revealed a subglottic mass. This was biopsied on suspicion of a neoplastic process. Due to the airway compromise, a tracheostomy was also performed. The biopsy was reported to reveal both acute and chronic inflammatory changes but no other specific features. A subsequent CT scan showed a mass arising from the posterior trachea occluding the trachea above the tracheostomy (Fig. 1).
Fig. 1.
CT of trachea showing posterior narrowing.
The patient was transferred to Great Ormond Street Hospital for further management. A subsequent microlaryngoscopy revealed that the lesion was sited in the immediate upper trachea (Fig. 2). The surrounding mucosa looked normal, thus giving the impression that the occlusion was due to posterior compression from an extrinsic rather than an intra-tracheal mass. The larynx and distal trachea were unaffected. Surgical exploration and excision of the mass was performed.
Fig. 2.
MLB: sessile posterior IMT.
At surgery, the trachea was accessed via an anterior horizontal neck incision. The trachea was opened anteriorly in the midline and the incision extended through the anterior cricoid. A smooth 1
cm mass behind the posterior tracheal wall was identified with an overlying small area of ulceration. An ellipse of the affected tracheal mucosa together with its deep tissue was excised.
Histopathological examination revealed non-specific superficial ulceration with granulation tissue formation and an underlying lesion composed of predominantly plump to ovoid spindle cells with a variably cellular architecture within a focally collagenous stroma. There was no cytological atypia and numerous admixed inflammatory cells were present including predominant lymphocytes and plasma cells. The spindle cells expressed smooth muscle actin (SMA) focally but did not demonstrate expression of CD34, desmin or CD117 (ckit). The histopathological features were those of an IMT. The deep resection margins appeared free from tumour (Fig. 3).
Fig. 3.
Histological findings. Photomicrographs of a retro-tracheal inflammatory myofibroblastic tumour (IMT) in an infant demonstrating (A) an unencapsulated cellular lesion composed of (B) plump spindle cells with (C) numerous admixed inflammatory cells including lymphocytes and plasma cells. (D) Smooth muscle actin (SMA) staining is positive confirming the myofibroblast phenotype.
The child made an excellent post-operative recovery. Follow-up with serial endoscopy and imaging will be arranged, due to the possibility of local recurrence.
3. Discussion
Clinical diagnosis of an IMT of the upper airway is often difficult. Non-specific symptoms such as dyspnoea, wheeze, dysphonia or dry cough have all been reported [7]. As in many cases with minor airway obstruction, asthma was suspected as the initial diagnosis. As medical therapy did not relieve the symptoms, a differential diagnosis should be further explored.
Radiological investigations (CXR and CT) together with endoscopy are essential for diagnosis of a suspected tracheal lesion.
On histopathological examination, the main differential diagnoses include infammatory changes secondary to foreign body, perforation or atypical infection, and other paediatric spindle cell tumours such as fibromatosis and myofibromatosis. The distinctive morphological characteristics of the admixed inflammatory component in addition to the immunohistochemical profile allow distinction of these entities, and in conjunction with imaging findings and other histological features, a final diagnosis may be reached. Due to the possible morphological similarities with other spindle lesions and secondary inflammatory changes, diagnosis may be difficult on the basis of needle biopsy alone for IMT, especially in cases which do not express CD117 [10].
Due to the young age of this patient, any intraluminal tumour can cause severe symptoms, including respiratory embarrassment and death. The only other reported tracheal lesion in an infant was found at post mortem of a 1-year-old who died of hypoxia from a plasma cell granuloma of the trachea [8].
It is generally accepted that the most appropriate management of IMTs is surgery. Radiotherapy has been suggested for cases that are inoperable, and spontaneous resolution has also been reported [9]. As clinically the lesion could be suspected as a neoplastic tumour, the use of a multidisciplinary team is essential to discuss further management. The case reported here required a tracheostomy to stabilise the airway prior to definitive treatment. This has associated morbidity and decannulation would be required for development of speech, and so a conservative course was not thought to be appropriate.
The treatment of choice for such lesions has been suggested to be endoscopic excision with or without the use of a laser (CO2 or Nd:YAG) [11], [12]. However, these case reports discuss lesions that are polypoid and intraluminal, which makes this surgical technique more favourable. The lesion reported in this case report was sessile and retro-tracheal, which meant endoscopic biopsy was not diagnostic. These factors suggested that an open approach should be adopted.
There have been reports of recurrence of such lesions, and so the patient will continue to have long-term follow-up.
4. Conclusion
IMT present in such a way that makes clinical diagnosis difficult. As with any upper airway lesion in a child, they may cause life threatening airway obstruction. Thorough investigation and access to a multidisciplinary team are essential in making a definitive management plan. This case highlights that these rare tumours, though usually present in adolescents, can occur in extremely young children. Also, while typically endoluminal tumours, they can occur extraluminally, as seen in this case. At surgery, an anterior trans-tracheal approach provided excellent access to the lesion and allowed for pathological complete excision.
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PII: S1871-4048(08)00039-7
doi:10.1016/j.pedex.2008.05.003
© 2008 Published by Elsevier Inc.
Volume 4, Issue 1 , Pages 25-28, January 2009
