Squamous cell carcinoma of the lung is one of the most common subtypes of lung cancers and belongs to the group of non-small cell lung carcinomas. Cigarette smoking is still recognized as the principal risk factor. Patients may be completely asymptomatic or present with dyspnea, cough, hemoptysis, weight loss, and an array of paraneoplastic syndromes. Imaging studies and a biopsy of the tumor are essential to identify the location, the extent of tumor progression, and the exact type.
Lung cancer is the most important malignancy-related death worldwide, causing more than 150,000 deaths in the United States alone every year . Two broad categories exist - small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC), with approximately 85% of new cases being NSCLC   . Squamous cell carcinoma of the lung (estimated to cause 400,000 deaths worldwide every year) comprises approximately 30% of all NSCLC cases    . Similarly to other subtypes, tobacco smoking remains the single most important risk factor for its development, while exposure to radon gas and asbestos are well-known risk factors as well    . The clinical presentation of lung cancer is highly variable. The diagnosis is made incidentally in a significant number of patients, as many are asymptomatic when lung cancer is detected  . Conversely, the progression of the tumor and several other factors (eg. location) may lead to symptoms such as dyspnea, chest pain, hemoptysis, weight loss, fatigue, and anorexia    . Numerous complications are documented, including pleural effusions, thromboembolic disease, together with several paraneoplastic syndromes that have been described   . Additionally, metastatic spread to various sites can produce characteristic symptoms - localized pain and fractures are seen with skeletal metastases; headaches, nausea, vomiting, and mental changes are main signs of cranial spread, whereas lymphadenopathy, hepatomegaly, and subcutaneous nodules are other notable findings . Given the limited choices of therapy for squamous cell carcinoma of the lung the prognosis remains poor, particularly in the case of metastatic spread .
The diagnosis of squamous cell carcinoma of the lung rests on a comprehensive clinical, imaging, and histopathological workup. Firstly, the physician should conduct a detailed patient history (during which the course of symptoms and their severity should be assessed) and perform a meticulous physical examination . Because of the insidious nature of lung cancer in general (including squamous cell carcinoma of the lung), this diagnosis should be considered in all cases who present with undisclosed respiratory and constitutional complaints. Plain radiography of the chest is the first imaging study the needs to be employed, which may show single or multiple masses, hilar enlargement, atelectasis, and many other findings that suggest a malignant process, but some patients have a normal X-ray if smaller tumors are present or if their location renders them poorly visible  . For this reason, computed tomography (CT) or positron emission tomography (PET) are recommended   . To discriminate between lung tumors and confirm the diagnosis of squamous cell carcinoma of the lung, it is necessary to perform a biopsy of the lesion. A CT-guided percutaneous biopsy or a flexible bronchoscopy with subsequent histopathological examination and immunohistochemistry can be done   . Additional methods that may be implemented are conventional bronchoscopy, mediastinoscopy, and aspiration cytology of pleural fluid, whereas electromagnetic navigation (EMN) bronchoscopy and radial endobronchial ultrasound (R-EBUS)-guided lung biopsy are novel techniques that show promising results   .