대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Papillary Squamous Cell Carcinoma in Background of Squamous Papilloma

Radiologic Findings

CT scan of the lower neck shows lobulating contoured protruding mass at the trachea. A cystic nodule in also seen in right upper lobe.
The patient has a history of laryngeal papilloma. Final diagnosis was made by tracheal biopsy.

Brief Review

A papilloma can be defined as a branching of coarsely lobulated tumor composed of epithelium-lined fibrovascular stalks arising from and projecting above and epithelial surface.
Squamous papillomas are the most common laryngeal tumors in children between 18 month and 3 years of age and are frequently multiple, a condition referred to as juvenile laryngeal papillomatosis, and usually limited to the larynx. Distal dissemination to the trachea, bronchi, and lung parenchyma occurs almost exclusively in patients with known laryngeal lesions, although quite rare, distal disease in the absence of laryngeal lesions is more common in adults than in children(1). Tracheal or proximal bronchial involvement occurs in only 5% of patients; 2% of all patients with laryngeal papillomatosis will eventually develop bronchial involvement. It typically occurs in children with juvenile papillomas, in whom a tracheotomy has been performed(2). The mechanism of dissemination is generally considered to be due to either aspiration of infectious fragments, which serve to establish new foci of tumor, or multicentric viral infection; both probably play a role(3).
Hoarseness is the most common initial symptom due to the laryngeal lesions. With dissemination, airway obstruction can result in wheezing, atelectasis, and recurrent pneumonia. Hemoptysis occurs frequently, and the clinical picture can resemble that of active tuberculosis or asthma(3).
Grossly, papillomas are polypoid or sessile masses within the airways. Distal papillomas, which begin to grow in the respiratory and terminal bronchioles, are composed of sheets of squamous cells that eventually proliferate within the alveoli and parasitize the pulmonary capillary bed as a blood supply. Central necrosis and/or communication of these nodular lesions with local airways can lead to cavitation. Cellular atypia is common in the parenchymal papillomas, and transformation to locally invasive squamous cell carcinoma is well known in the patients, and the risk of this malignancy increases with the duration of disease(4).
CT scans show small nodules or nodular thickenings, occasionally carpeting part or the entire trachea. Bronchial involvement has similar findings(3,5). Involvement of distal airway results in multiple nodular opacity frequently associated with cavitation. Since papillomas disseminate via the airways, a centrillobular distribution of opacities or small nodules would be expected. Cavitation is frequent and superficially resembles cystic bronchiectasis, although CT studies reveal absence of dilatation of airways leading to the cavity. The wall of the cavities typically shows a smooth surface and uniform thickness(3,4).
Although papillomas often regress at puberty or are successfully treated by surgical excision in children with isolated laryngeal disease, distal lesions do not tend to improve spontaneously.

References

1. Al-Saleem T, Peale AR, Norris CM. Multiple papillomatosis of the lower respiratory tract: clinical and pathologic study of eleven cases. Cancer 1968; 22: 1173-1184
2. Maria-Benedict Franzmann, Christian Buchwald, Per Larsen, Viggo Balle. Tracheobronchial involvement of laryngeal papillomatosis at onset. The Journal of laryngology and otology 1994; 108: 164-165
3. Gruden JF, Webb R, Sides DM. Adult-onset disseminated tracheobronchial papillomatosis : CT features. J Comput Assist Tomogr 1994; 18: 640-642
4. Kramer SS, Wehunt WD, Stocker JT, Kashima H. Pulmonary manifestations of juvenile laryngotracheal papillomatosis. AJR 1985; 144: 687-694
5. McCarthy M, Rosado-de-Christensen ML. Tumors of the trachea. J Thorac Imaging 1995; 10: 180-198

Keywords

Airway, Malignant tumor,