000 Squamous Cell Carcinoma

Definition

Squamous cell carcinoma (aka epidermoid carcinoma) is a malignant condition of the airway epithelium, usually arising from the central portions of the airways and has a strong causative association with smoking. It is the second most common lung cancer, making up 30% of cases.

Structurally squamous cell carcinoma is characterized by its central location and occurs more commonly in the upper lobes. It tends to spread locally to regional nodes and may cavitate which is a characteristic feature of squamous cell carcinomas in general.

The histopathology is characterised by the proliferation of flat fish-scale like cells and may be associated and characterized by the production of keratin and intercellular bridges. Well differentiated SCC contains keratin pearls. The cells have large irregular nuclii, large nucleoli, and coarse chromatin. The cells are arranged in sheets.

Metaplasia, dysplasia, and carcinoma in situ are sometimes present in the tissue surrounding the carcinoma.

Metastatic disease does occur but compared to other lung cancers it is relatively uncommon occurring in <20% at presentation.

Clinically it often produces symptoms of cough dyspnea or atelectasis, wheezing or hemoptysis since it is more central in its location and affects larger airways. It is also the lung malignancy that is most often associated with hypercalcemia

From a diagnostic point of view, its central location and tendency to exfoliate enables cytological diagnosis from the sputum or bronchial washings.

Treatment is based on staging so that stages I, II, and IIIA have curative and surgical possibility, stage IIIb and more advanced are treated with combinations of radiotherapy and chemotherapy