Skin Cancer Care Guide

Squamous Cell Skin Cancer

Squamous cell carcinoma is a common form of lung cancer, accounting for approximately one-third of all cases of bronchogenic carcinomas. Unlike adenocarcinoma, it is strongly linked with a history of cigarette smoking. Its histogenesis may be related to chronic inflammation and injury of the bronchial epithelium, which leads to replacement of the normal ciliated columnar epithelium by a squamous epithelium. This transformation from a glandular epithelium to squamous epithelium is known as squamous metaplasia.

Histolory studies have revealed a series of changes that occur over many years and represent a morphologic progression to bronchogenic carcinoma. Early changes include a loss of the ciliated columnar epithelium, basal cell hyperplasia, and the formation of a low columnar epithelium without cilia. These changes are followed by a squamous metaplasia. As cellular atypia develops and advances there is progression through mild, moderate and severe dysplasia to carcinoma in situ. Carcinoma in situ has no metastatic potential. However, once carcinoma in situ penetrates the basement membrane to involve the lamina propria, it is invasive carcinoma and capable of widespread dissemination. These progressive changes are similar to those that proceed the development of squamous cell carcinoma in the uterine cervix. This progressive sequence would suggest that it would be possible to detect abnormalities that are linked to bronchogenic carcinoma.

Most squamous cell carcinomas arise centrally from either the main, lobar or segmental bronchi and ulcerate through the mucosa into the surrounding lung parenchyma. Their central location also tends to produces symptoms at an earlier stage than tumors located peripherally. Although symptoms tend not to be specific, most commonly a non-productive cough, they stem from the involvement of vital structures at the hilar area of the lung. Most patients, however, are detected by a routine chest radiograph, before they are symptomatic. Larger tumors are associated with chest pain, loss of appetite, loss of weight and dyspnea on exertion.

Despite the fact that squamous cell carcinomas are rare, they can cause a characteristic radiographical and clinical syndrome. They are the most common cause of the Pancoast or superior sulcus syndrome. Endobronchial squamous cell carcinoma commonly leads to bronchial obstruction and post obstructive pneumonia. The common radiologic manifestations of squamous cell carcinomas result from the partial or total bronchial obstructions which leads to pneumonia or atelectasis. One characteristic radiographic sign is the “S sign of Golden” which is due to the inability of the upper lobe to completely collapse. The tumor causes the bulging of the minor fissure on the right leading to a sigmoid shape.