Squamous cell papilloma of the lung

Definition

A benign papillary tumour consisting of fronds covered by squamous epithelium, it may be solitary or multiple, exophytic or inverted.

Epidemiology

This rare tumour comprises less than 0.5% of all lung tumours. It occurs predominantly in male smokers1. Multiple tumours are present in laryngotracheal papillomatosis, which occurs as an aggressive disease in children4, more indolent in adults2. Human papilloma virus, types 6 and 11 are thought to have a role in the aetiology of benign papillomas3,9, with types 16 and 18 associated with malignant transformation5,6.

Clinical features

Patients present with obstructive symptoms3.

Radiology

CT shows a small endobronchial lesion. If peripheral lesions are present, there are nodular opacities

Macroscopic appearances

The papillomas have a cauliflower-like appearance.

Histopathology

The great majority are exophytic, but an inverted variant has been reported1. A loose fibrovascular core is covered by stratified squamous epithelium with orderly maturation. Wrinkled nuclei and koilocytes may be apparent1,10. There may be the occasional large atypical cell. Dysplasia1 occurs and occasionally squamous carcinomas arise from papillomas.

Inverted lesions show invaginations which may involve seromucinous glands, but there is a continuous basement membrane. Alveolar involvement occurs, with solid nests of bland squamous cells surrounded by type II pneumocytes. In lower respiratory tract involvement, viral cytopathic changes are ubiquitous.

Immunohistochemistry

Increased p53 expression may be a marker of malignant transformation2.

Differential diagnosis

Management

Prognosis

Papillomas may recur locally. Laryngotracheal papillomatosis may spread into the bronchi. Papillomatosis may undergo malignant transformation2. Papillomatosis may be fatal due to obstructive complications, even without malignant transformation.

References

Tumours of the Lung, Pleura, Thymus and Heart. WHO Classification of Tumours. IARC Press 2004.

1Flieder DB, Koss MN, Nicholson A, et al. Solitary pulmonary papillomas in adults: a clinicopathologic and in situ hybridization study of 14 cases combined with 27 cases in the literature. Am J Surg Pathol 1998; 22:1328-42

2Gupta D, Holden J,Layfield L. Topoisomerase alpha II, retinoblastoma gene product, and p53: potential relationships with aggressive behavior and malignant transformation in recurrent respiratory papillomatosis. Appl Immunohistochem Mol Morphol 2001; 9:86-91

3Katial RK, Ranlett R,Whitlock WL. Human papilloma virus associated with solitary squamous papilloma complicated by bronchiectasis and bronchial stenosis. Chest 1994; 106:1887-9

4Magid MS, Chen YT, Soslow RA, et al. Juvenile-onset recurrent respiratory papillomatosis involving the lung: A case report and review of the literature. Pediatr Dev Pathol 1998; 1:157-63

5Popper HH, el-Shabrawi Y, Wockel W, et al. Prognostic importance of human papilloma virus typing in squamous cell papilloma of the bronchus: comparison of in situ hybridization and the polymerase chain reaction. Hum Pathol 1994; 25:1191-7

6Popper HH, Wirnsberger G, Juttner-Smolle FM, et al. The predictive value of human papilloma virus (HPV) typing in the prognosis of bronchial squamous cell papillomas. Histopathology 1992; 21:323-30

7Roglic M, Jukic S,Damjanov I. Cytology of the solitary papilloma of the bronchus. Acta Cytol 1975; 19:11-3

8Spencer H, Dail DH,Arneaud J. Non-invasive bronchial epithelial papillary tumors. Cancer 1980; 45:1486-97

9Syrjanen KJ. HPV infections and lung cancer. J Clin Pathol 2002; 55:885-91

10Trillo A,Guha A. Solitary condylomatous papilloma of the bronchus. Arch Pathol Lab Med 1988; 112:731-3

 

This page last revised 8.4.2005.

©SMUHT/PW Bishop