RADIOLOGICAL DIAGNOSIS
Diagnosis of the case presented in the previous edition
J Bras Pneumol 2004; 30(3):299
ADENOID CYSTIC CARCINOMA OF THE LEFT MAIN BRONCHUS
Diagnosis made through bronchoscopy-guided biopsy of a mass in the left main bronchus.
Description
Chest X-ray:
Total opacification of the left hemithorax with dislocation of the ipsilateral mediastinal structures (atelectasis)
Computed tomography of the chest with contrast:
Obstruction of the proximal portion of the left main bronchus caused by hypoattenuation of a lesion measuring approximately 2 x 3 cm, spreading the atelectasis to the entirety of the left lung, with dislocation of the ipsilateral mediastinal structures and compensatory hyperinflation in the right lung.
Comments
Adenoid cystic carcinoma (ACC), once known as cylindroma, is a low-grade malignancy that originates in the tracheobronchial mucous glands. It is one of the most common malignant tumors of the trachea, second only to squamous-cell carcinoma.
The tumor typically appears after the age of 40 and may present unspecified symptoms such as cough, wheezing and dyspnea.
There is no correlation with smoking, nor is there any gender-based predominance.
The lesion generally grows along the tracheobronchial wall, infiltrating long stretches of the submucosa. It is locally invasive, and the rate of post-resection recurrence is high. It is most frequently seen in the posterolateral wall of the lower two-thirds of the trachea.
Upon diagnosis, the tumor measured more than 2 cm in mean diameter.
Regional lymph-node metastases are seen in 10% of patients.
ACC occurs most frequently in the salivary glands, although it may also appear in other locations such as the breast, skin, uterine cervix, upper respiratory/digestive tracts and lungs.
The imaging characteristics are similar to those of squamous-cell carcinoma and the differential diagnosis is difficult to make through imaging alone.
The presentation is as an intraluminal mass with irregular contours that may be lobulated or smooth. The base of the lesion may either be wide and polypoid or pedunculated.
The circumferential invasion may create the impression of tracheal stenosis.
In simple X-rays, smooth or nodular thickening of the tracheal wall, with concomitant luminal narrowing, is seen.
An accurate evaluation of the extraluminal aspects of the tumor can be made through computed tomography.
References
Albers E, Lawrie T, Harrell JH, Yi ES. Tracheobronchial adenoid cystic carcinoma: a clinicopathologic study of 14 cases. Chest. 2004 Mar;125(3):1160-5.
McCarthyy MJ, Christenson MR. Tumors of trachea. Journal of thoracic imaging. 1995, 10:180-198
Cotran RS, Kumar V, Robbins SL. Robbins. Patologia Estrutural e Funcional. 5a. Edição. Editora Guanabara Koogan S.A. , Rio de Janeiro, RJ, 1996.
McLoud TC: Thoracic Radiology: The Requisites. St. Louis, CV Mosby Co, 1998.
Dahnert W. Radiology Review Manual, Third Edition. Baltimore: Williams and Wilkins. 1996.
Correct diagnoses of the case presented in the May/June 2004 issue:
There were no correct responses.
Publication Dates
-
Publication in this collection
28 Sept 2004 -
Date of issue
Aug 2004
