Adenoid cystic carcinoma of the tracheobronchial tree

Adenoid cystic carcinomas (ACC's) of tracheo-bhronchial tree are a type a low grade tracheal tumour. They are considered the second most common primary tumour of the trachea ³.

Epidemiology

They are usually first recognized in patients in their 40s. There is no recognised gender predilection. 

Clinical presentation

Symptoms in patients with adenoid cystic carcinoma are usually related to airway obstruction and therefore includes dyspnoea, cough, stridor, wheezing, and haemoptysis. 

Pathology

The tumors may be histologically classified into tubular, cribriform, and solid subtypes ⁶.

The tumours are usually low grade but an occasionally undergo high grade tranformation ⁷. 

Smoking does appear to affect the incidence.

Location

Adenoid cystic carcinomas usually arise in the lower trachea . Less commonmy they are found in the mainstem bronchi, lobar bronchi and rarely rarely, in the segmental bronchi and extrathoracic trachea.

Radiographic features

CT chest 

On CT, these tumours have a notable tendency toward submucosal extension and typically manifests as either 

• an intraluminal mass of soft-tissue attenuation with extension through the tracheal wall or
• diffuse or circumferential wall thickening of the trachea, a soft-tissue mass filling the airway or 
• a homogeneous mass encircling the trachea with wall thickening in the transverse and longitudinal planes. 

The longitudinal extent of the tumours are greater than their axial extent and the tumors usually involve more than 180° of the airway circumference. 

They can be variable in shape rangin from polypoid to broad broad-based. Their margins are also variable and ranges from smooth to lobulated lobulated to irregular irregular. Intratumoural calcification is rare.

See also

• tracheal masses 
• adenoid cystic carcinoma - general
  • adenoid cystic carcinoma of lung