Detection of lung cancer on a chest radiograph may be made either by identifying the mass itself, metastases or secondary effects of the mass. There are several different cell types.
Adenocarcinoma is currently the most common type of lung cancer (50% of all cases). It typically presents as a peripheral nodule. It can be associated with areas of fibrosis or bullous disease. Bronchioloalveolar carcinoma is a subset of adenocarcinoma. It can present as a nodule, multiple nodules or an alveolar infiltrate.
Squamous cell carcinoma accounts for approximately 33% of all lung cancers. It is strongly associated with cigarette smoking. It is the most common lung cancer to cavitate, to cause hypercalcemia and to cause Pancoast tumor. Squamous cell tumors are centrally located and endobronchial. They can present with atelectasis or post-obstructive pneumonia. (This is why we recommend a 4-6 week follow-up chest film in adults with pneumonia to ensure complete resolution.)
Large cell carcinoma is an undifferentiated relatively rare (5%) tumor. It usually presents as a large (>3cm) peripheral mass.
Small cell carcinoma accounts for about 15% or lung cancers and is strongly associated with smoking. It grows rapidly with early metastases. It is the most common cell type to cause ectopic hormone syndromes. These tumors are usually located centrally. They are the most common lung cancer to cause superior vena cava syndrome.